Blastocystis occurrence in water sources worldwide from 2005 to 2022: a review

There has been increasing interest in the study of Blastocystis in the last two decades. Many studies have been carried out in human and animal hosts including environmental sources, but there is little or no information on the occurrence of Blastocystis in water sources worldwide. Therefore, this study aimed at assessing the occurrence of Blastocystis in water sources across the world from 2005 to 2022, noting the method of detection and the distribution of the subtypes from various water sources. A literature search was performed on internet-based databases including Google search, PubMed, Scopus, and Web of Science. Upon application of the criteria for inclusion, 25 articles revealing the occurrence of Blastocystis in water sources in 15 countries were included in the review. Blastocystis occurrence varies across water sources ranging from 0% in a drinking water source in Venezuela to 100% in rivers; well water, stored water, and fishpond in Nepal and Malaysia; and fountain water, irrigation water, and rainwater in Italy, Spain, and Thailand. The occurrence of the parasite was significantly associated with the coliform count, temperature, conductivity, dissolved oxygen, turbidity, total dissolved solids, and chemical oxygen demand. A total of 11 Blastocystis subtypes were identified in water sources worldwide, namely, ST1-ST8, ST10, ST23, and ST26 in which ST1 and ST3 were the most prevalent subtypes. Considering the importance of Blastocystis as a waterborne parasite, the subtype distribution and morphological distinction in water sources need to be carried out using molecular and electron microscopic techniques. Existing studies have covered only about 10% of the world's countries.

Primary dysmenorrhoea among reproductive-age women at Kuala Selangor health clinic: Prevalence and factors associated

INTRODUCTION

Primary dysmenorrhoea (PD) is a frequent gynaecological condition in adolescents and adult women worldwide, affecting their daily activity and leading to a lower quality of life. The purpose of this study is to determine the prevalence, severity, and factors associated with PD among reproductive-age women at Kuala Selangor Health Clinic.

MATERIALS AND METHODS

This cross-sectional study used systematic random sampling at the Kuala Selangor Health Clinic from 3rd July to 29th September 2017. This study included 213 women between the age of 18 and 35 years old. The questionnaires consist of sociodemographic, lifestyle activities, and menstrual history components with Numerical Rating Scale (NRS) for menstrual pain as well as the Pictorial Blood Assessment Chart (PBAC) to quantify the blood loss during menstruation.

RESULTS

A total of 210 women participated in this study with a response rate of 98.6%. The prevalence of PD was 60.5% with 13.4%, 75.6%, and 11.0% for mild, moderate, and severe in intensity, respectively. Nulliparous (OR: 5.1, CI: 1.508, 17.277, p = 0.009), first-degree family history of dysmenorrhoea (OR: 4.431, CI: 1.727, 11,368, p = 0.002), heavy menstrual blood flow (OR: 11.6, CI: 2.849, 47.53, p <0.001), and lack of regular physical exercise (OR: 14.037, CI: 5.161, 38.183, p < 0.001) were found as the significant association for PD. Meanwhile, having a short menstruation reduces the risk of PD during menstruation (OR: 0.04, CI: 0.004, 0.391, p = 0.006).

CONCLUSION

PD is prevalent among reproductive-age women. Physical exercise is a protective factor for PD, hence health care providers particularly those in primary care settings should regularly counsel and encourage women to be physically active.

Clinical and Radiological Features of Pseudomyxoma Peritonei

Pseudomyxoma peritonei is due to diffuse involvement of the peritoneal cavity with mucinous material. Four patients were found in two major general hospitals in Riyadh. All patients were male. Cardinal clinical features were abdominal distension, pain and weight loss. Computed tomography was helpful preoperatively. Laparoscopy or laparotomy were performed to arrive at a correct diagnosis.

W/M serrated osteotomy for infantile Blount's disease in Ghana: Short-term results

PURPOSE

The W/M serrated high tibial osteotomy is a not frequently described surgical technique for simultaneously correcting the varus and torsional deformity in patients with Blount's disease. Without the need for internal fixation, this surgical treatment is well suited for developing countries. This study describes the short-term results of the bilateral and unilateral W/M serrated osteotomy in patients with infantile Blount's disease.

METHODS

Between May 2008 and January 2013, 52 patients were treated with uni- (n = 22) or bi-lateral (n = 30) W/M serrated osteotomy of the proximal tibia due to a tibial varus deformity in two district hospitals in Ghana. Other causes than infantile Blount's disease were excluded from the analysis. Pre- and post-operative clinical and radiological measurements were done, and complications were monitored up to 12 weeks after surgery.

RESULTS

Seventeen patients (five males, 12 females; mean age 4.9 [standard deviation: 2.10]) were included, which underwent a total of 25 W/M serrated osteotomies. The femorotibial angle was corrected from 34.1° ([mean] range: 6-68°) to - 7.1° ([mean] range: -28-5°). Only one patient had developed a wound infection, and all reached full consolidation.

CONCLUSIONS

The W/M serrated osteotomy seems a profitable alternative technique for treating the varus and torsional deformity in patients with Blount's disease in the circumstances of developing countries. The short-term outcomes are good and promising with a low complication rate and good consolidation. Long-term follow-up results of these patients are needed to observe possible complications.

LEVEL OF EVIDENCE

IV, therapeutic case series.

Zooplankton Composition and Abundance as Indicators of Eutrophication in Two Small Man-made Lakes

The distribution and abundance of zooplankton species of Harapan and Aman Lakes were investigated in relation to physical parameters and chlorophyll-a content. Both lakes were characterised by the occurrence of algal bloom problem. The composition of zooplankton was collected at monthly intervals from November 2013 to February 2014. The total number of taxa in Harapan and Aman Lakes were 23 and 27, respectively. Rotifera was the highest abundance group represent 64% of the total species recorded followed by Copepoda (29%) and Cladocera (7%). Three dominant zooplankton that been recorded in both the lakes are Brachionus forficula, Brachionus nilsoni, and Trichocerca sp. High abundance of these species indicates that the lakes are eutrophic water bodies. Overall, zooplankton species distribution and abundance in the study sites are influenced by various environmental factors such as water transparency and chlorophyll-a content.

Synthesis of 1,2-unsaturated pyranosylphosphonate nucleosides from 3,4,6-tri-O-acetyl-D-glycal

Ferrier rearrangement of 3,4,6-tri-O-acetyl-D-glucal (1) in the presence of triethylphosphite afforded the 2,3-unsaturated pyranose 2. Deacetylation and simultaneous migration of the double bond to 1,2-position in the sugar moiety was achieved by stirring in sodium ethoxide. Tosylation with one equivalent of tosyl chloride afforded 4. Nucleophile displacement of the tosylate of 4 with nucleobase in the presence of NaH/DMF followed by deprotection gave the desired 1,2-unsaturated pyranosylphosphonates 7a-c.

Beta-endorphin and components of emotionality discriminate between physically active and sedentary men

Differences between physically active and sedentary men were tested by profile comparison. The study identifies the relative importance of circulating beta-endorphin (BE), atherosclerotic disease risk (ADR) index, and selected components of emotionality in discriminating between physically active and sedentary men. The subjects were psychologically normal and medically healthy middle-aged men. Jogging activity was the subject classification criterion. The data were collected on selected physiological (treadmill), biochemical (blood collected from resting subjects), and psychological (Eysenck and MMPI) variables. The physical fitness score (PFS) was used as an index of fitness. Physically active men with a high PFS (n = 21), when compared to the sedentary men with a low PFS (n = 15), exhibited lower basal plasma BE, lower ADR, lower anxiety index (AI), and lower MMPI depression score (D). Canonical correlation analysis showed that PFS and BE in one set were correlated with D and neuroticism (NS) in another set of variables. Discriminant function analysis showed that the AI was the most powerful discriminator between the physically active and sedentary men, followed by BE and NS. Interestingly, BE and NS exhibited the same magnitude of discrimination power. The ADR exhibited less discrimination power, relative to AI, BE, and NS. In conclusion, the physically active men, compared to the sedentary men in this study, exhibited lower basal plasma BE, which appeared to be associated with less atherosclerotic disease risk, less neuroticism, less anxiety, and less depression.

Decreases in resting plasma beta-endorphin/-lipotropin after endurance training

The purpose of the present study was to investigate changes in the resting plasma beta-endorphin/-lipotropin (beta E/beta-LPH) concentration that may occur with exercise training. A treatment group (N = 10) of previously sedentary, psychologically normal, and medically healthy middle-aged men trained for 4 months in a structured fitness program. The treatment group was compared with two age-matched groups: a jogger group (N = 10) and a sedentary group (N = 10). Venous blood was collected in the early morning after the subjects had been fasting for at least 12 h. The subjects were also resting at the time of blood collection. Resting plasma beta E/beta-LPH (measured by radioimmunoassay) decreased (P less than 0.05) following the 4 months of exercise training in the treatment group, from 11.01 +/- 1.62 (SE) to 7.22 +/- 0.99 pmol.1-1. The jogger and sedentary groups demonstrated no changes in the resting plasma beta E/beta-LPH concentration following the 4 months. Aerobic fitness, measured by the maximal oxygen uptake (VO2max), increased (P less than 0.01) from 36.56 +/- 2.58 (SE) to 44.85 +/- 1.34 ml.kg-1.min-1 in the treatment group after the 4 months of training. There were no changes in VO2max for either the jogger group or the sedentary group following the 4 months. In conclusion, beta E/beta-LPH in the plasma of resting middle-aged men appeared to be decreased after 4 months of aerobic training.

Effects of exercise on cardiovascular disease risk in women with NIDDM

The effect of a 4-month exercise program on measures of cardiovascular disease (CHD) risk was observed in women (mean age = 59.2 +/- 3.9 years) of postmenopausal years with NIDDM, who demonstrated fair to normal control of blood glucose control. The women were randomly assigned to either an exercise (n = 5) or control (n = 5) group. Initially, both groups had a similar body mass index, resting heart rate and blood pressures, blood glucose and hemoglobin A1. After 4 months, the exercise group demonstrated a 32% increase (P less than 0.03) in both absolute and relative maximum oxygen uptake (VO2) while the control group remained unchanged. Significant differences were found between the exercisers and non-exercisers for absolute (F(1,8) 4.94, P = 0.057) and relative (F(1,8) 7.67, P = 0.024) maximum VO2 from pretest to posttest. Body weight (kg) and body fat (%) remained unchanged for both groups. Although total cholesterol was found to be reduced by 13% for the exercise group (P less than 0.03) and 11% for the controls (P less than 0.01), a 15% decrease (P less than 0.03) in high-density lipoprotein (HDL) was observed for the control group, only. Hence, a marked difference (P less than 0.03) in the risk ratio was observed between the exercise and control groups. These data suggest that physical exercise may play an important role in the maintenance of HDL mass and in the reduction of CHD risk factors in women of postmenopausal years with NIDDM.

Tumoral calcinosis: case reports from Saudi Arabia with a review of the literature

Tumoral calcinosis is a rare disease mainly reported among blacks, especially from the tropical and sub-tropical regions of Africa. Hitherto, no reports of this disease entity have been reported from North Africa and the Arab Peninsula. This paper is therefore the first documentation of tumoral calcinosis in nine patients from the Arabian Peninsula; seven of whom are Saudis and two Yemenis. Peculiar osseous and joint changes co-existed in one of the cases. Moreover, there was a high incidence in the feet, in 75% of cases. One of the lesions was quite extensive. Reason for these changes are suggested.

Structural changes of the diaphragmatic peritoneum in patients with schistosomal hepatic fibrosis: its relation to ascites

The histopathologic changes of the peritoneum of the hemidiaphragm were studied in 30 patients with schistosomal liver disease and compared with ten control subjects. The diaphragmatic peritoneum of patients with ascites was markedly thickened with infiltration of inflammatory cells and collagen bundles resembling the interstitial changes of peripheral lymphedema. Obliteration of diaphragmatic lymphatic stomata with restricted lymph flow as well as excess lymph formation from portal hypertension are both major factors in the magnitude and intractability of ascites associated with schistosomal hepatic fibrosis.

Impact of physical fitness on strategy development in decision-making tasks

Data from 30 female subjects indicated that a 17.3% increase in a physical fitness index improved by 12% to 68% the information processing and decision-making capabilities of the subjects. The changes in physical fitness did not affect the performance on a variety of other tasks.

Serum lipids: interactions between age and moderate intensity exercise

The purpose of this study was to examine relationships between age and selected serum lipids and lipoproteins in women before and after a physical fitness programme. Twenty females 27-59 years of age who had participated in the Purdue University Physical Fitness Programme were selected and placed into one of two groups: "junior" (mean age 34, all under 40 yrs) or "senior" (mean age 50, all over 43). A two way factorial design was used to study differences in serum triglycerides (TG), total cholesterol (TC), low density lipoprotein cholesterol (LDLC), high density lipoprotein cholesterol (HDLC), and the risk ratios TC/HDLC and LDLC/HDLC associated with physical fitness and the eight month physical fitness programme. The ability of the biochemical variables to discriminate between the age groups was investigated using discriminant function analyses. The analyses of variance indicated that although the two age groups were matched on the basis of a multivariate physical fitness score (Ismail et al, 1965) the older group was heavier (p less than 0.05), and had higher systolic and pulse pressures (p less than 0.05). Both groups increased their physical fitness score from pre to post programme (p less than 0.01). No significant age related biochemical differences were noted in the univariate analyses; however, in the discriminant function analyses the biochemical variables significantly discriminated between the two groups before, but not after the programme. A decrease in serum triglycerides was observed in the more highly fit women in each age group. These findings suggest that moderate levels of physical activity may help to counteract some of the undesirable changes in the lipid profile associated with age.

Relationships between urinary catecholamine metabolites, particularly MHPG, and selected personality and physical fitness characteristics in normal subjects

Thirty-four normal male subjects were tested to determine the relationships between physical fitness condition (Ismail criterion), levels of self-reported depression (MMPI) and anxiety (Welsh criterion), and the urinary concentrations of 3-methoxy-4-hydroxyphenylglycol (MHPG), normetanephrine (NM), and metanephrine (M). Urinary samples were collected after sleep and during occupational activities to ascertain the effects of different psychosocial stimuli on the relationships among the variables. Univariately, urinary MHPG did not relate to physical fitness and was moderately related to depression (p less than or equal to 0.10) during the occupational period. Multivariate canonical correlational results revealed a significant (p less than or equal to 0.04) relationship between the biochemical and personality sets of variables during the occupational settings. MHPG was the most sensitive catecholamine metabolite for reflecting depressive conditions. The results suggest a biochemical reactivity syndrome involving MHPG that may relate to depressive personality characteristics.

Influence of catecholamine activity on the hierarchical relationships among physical fitness condition and selected personality characteristics

Tested male Ss (N = 34) to determine how changes in the urinary excretion patterns of selected catecholamines and their metabolites affect the multivariate relationships involving variables that measure physical fitness condition and selected personality characteristics. Urine specimens were collected from each S after sleep and during occupational activities and analyzed for six catecholamine-related variables. Those measures were combined with six personality variables (MMPI) and a physical fitness score (Ismail Criterion), and subjected to first- and second-order factor analyses. The findings indicated an association between low physical fitness and high self-reported anxious depression during the occupational period, but not at rest. The changes in the factor structures were statistically mediated by changes in the concentrations of the biochemical variables across the collection periods. This suggests that the relationships between physical fitness and personality are augmented during catecholamine reactivity to occupational stress.

Depression as a powerful discriminator between physically active and sedentary middle-aged men

This study identifies the relative importance of psychological dimensions that discriminate between habitually physically active and sedentary men. The data support the notion that physical activity has psychological benefits. Subjects (N = 22) were normal, medically healthy middle-aged men (40-60 years of age). Data were collected on selected physiological (treadmill) and psychological (MMPI) variables and replicated within four months. The Student's t-test and discriminant function analysis were used in the statistical analysis. Physically active men (n = 11) have lower depression (scale 2) and lower social introversion (scale 10) than the sedentary men (n = 11). The physically active men may exhibit MMPI scale differences in 'neurotic' tendencies from the sedentary men, but there is no apparent difference in scales suggestive of 'psychotic' tendencies. Depression (scale 2) is the most powerful discriminator between physically active and sedentary men, followed by hysteria (scale 3) and social introversion (scale 10). In conclusion, our data identify depression as the most important MMPI scale that discriminates between physically active and sedentary men.

Intellectual differences of adult men related to age and physical fitness before and after an exercise program

Fluid and crystalized intelligence differences among high-fit, young; high-fit, old; low-fit, young, and low-fit, old groups were investigated before and after an exercise program. The high-fit group had higher fluid intelligence than the low-fit group. Likewise, the young group scored higher than the old group. The four groups scored higher at the posttest on two of the fluid intelligence subtests of the Cattell Culture. Fair Intelligence Test. No differences were observed on crystallized intelligence. It is uncertain how biological factors and psychological changes, either individually or in combination, produce differences in cognitive functioning due to physical fitness.

Prediction of serum testosterone before and after an exercise program using physiological and personality variables

This study investigated the relationships between serum testosterone level and selected physiological and personality variables in 58 males (21-61 years) before and after a four month physical fitness program consisting of jogging, calisthenics, and recreational activities. Physical fitness scores were obtained for each subject using a regression equation. Serum testosterone was determined using a radioimmunoassay technique. The multiple correlation was used to determine the relationship between serum testosterone and 19 independent variables consisting of age, height, and weight, and percent lean body weight, systolic and diastolic blood pressures, ten factors from the Cattell 16 PF and the three scales of the Eysenck Personality Inventory. A stepwise linear regression was used to identify the predictive power of each of the independent variables. The subjects improved significantly in physical fitness (p < 0.01). The multiple correlations both at the pre-test (R=0.77; R2=0.59) and post-test (R=0.67; R2=0.46) were significant at the 0.01 level. Neuroticism, factors dealing with emotional stability, aggression, and intelligence were powerful predictors initially. Similar results were obtained at the post-test except for the addition of percent lean as a powerful predictor and the absence of factors dealing with intelligence and aggression. The emergence of percent lean was seen to reflect changes in body composition associated with testosterone secretion. The absence of aggression at the post-test was interpreted in light of free catecholamine excretion associated with habitual exercise.

The effect of a four-month physical fitness program on a young and an old group matched for physical fitness

A young (X = 36.8 years) and an old (X = 52.9 years) group (n = 12) matched for physical fitness performed a graded exercise test at the beginning and after a 4-month physical fitness program consisting of calisthenics, jogging, and recreational activities. The purpose of the study was to determine if there were any differences in response to physical training in the two age groups of similar fitness. Sixteen physiological and four biochemical variables were measured. There was no significant difference in VO2 max between the young and old groups. Also, there were no significant differences between groups for serum total lipids, cholesterol, triglycerides, or glucose levels. The effects of the training program were similar for both the young and old groups.

Serum insulin and glucose response to graded exercise in adults. Part II. The effect of exercise conditioning

The effect of conditioning to severe exercise upon serum immunoreactive insulin levels (IRI) and serum glucose concentrations (GC) was studied in active and sedentary groups of middle-aged men. The responses of serum IRI and serum GC were determined during graded cycle ergometer exercise which required similar low and high relative work intensities, before (pre) and after (post) a four month physical fitness programme. Both groups demonstrated a marked decline in serum IRI during high intensity exercise from pre to post tests, and a tendency to maintain serum, GC (sedentary group) or elevate serum GC (active group) during exercise, following the conditioning programme. The data provides evidence of a bi-directional response of serum IRI and serum GC to graded exercise, with only minor modifications in the response patterns resulting from exercise conditioning.

Multivariate interrelationships of selected physiological and biochemical variables associated with physical fitness status

The interrelationships between selected physiological, metabolic and hormonal variables were investigated in active and sedentary middle-aged males during consecutive periods of rest, graded exercise on a bicycle ergometer, and recovery. Venous blood samples were drawn during each phase of the activity which was performed in the post-absorptive state. Data were analysed using correlational and factorial analysis techniques, and further evaluated by discriminant function procedures. Significant correlational relationships were evident among physiological, metabolic and hormonal variables, and factor analysis identified four factors at each phase of activity which accounted for as much as 69% of the common extracted variance. These factors described physiological function and hormone-metabolite behaviour during each phase of activity. Discriminant function allowed fitness classification of subjects using only the hormone-metabolite data, thus identifying specific biochemical correlates of the fitness groupings which had been established by physiological criteria alone.

Serum insulin and glucose response to graded exercise in adults. Part I: the influence of fitness status

The effect of acute exercise upon serum immunoreactive insulin levels (IRI) and serum glucose concentrations (GC) was studied in groups of middle-aged men of contrasting physical fitness status. Two groups of subjects, one active and one sedentary (both N = 11, mean age 44 years), performed a graded cycle ergometer exercise test in the post-absorptive state. Venous blood samples were taken at rest, during low and high work intensities, and after recovery. The response of serum IRI to exercise was similar in both groups of subjects with significant increases observed during exercise followed by a return to resting values during recovery. However, the magnitude of serum IRI response was lower in the active group. In contrast, the sedentary group demonstrated little or no change in serum GC during exercise, whereas significant increases in serum GC were observed during exercise in the active group.

Effects of exercise on free serum cholesterol

Two age groups (young and old, n = 12) matched for physical fitness and two physical fitness groups (high and old, n = 12) matched for age participated in a four month physical fitness programme. Blood samples were drawn at four stages of metabolic stress at the pre-test and five stages at the post-test. The blood samples were analyzed by colorimetric methods for total cholesterol and free cholesterol. Statistical analysis revealed that: (1) Short-term exercise increased total cholesterol, free cholesterol, and the percent free cholesterol from the resting state to the submaximal and maximal exercise states. (2) There was no change in free serum cholesterol from the pre- to post-tests. (3) The high-fit group, compared with the low-fit group, had a lower free cholesterol level but had similar percent free cholesterol values. (4) There was no significant difference between age groups for either total serum cholesterol, free cholesterol, or the percent free cholesterol levels.

Effect of prolonged exercise of serum testosterone levels in adult men

The purpose of the study was to: 1) identify the differences in serum testosterone levels among four groups of adult men differentiated on the basis of physical fitness and age, and 2) determine the effect of a four-month physical fitness programme consisting of running, calisthenics and recreational activities on the serum testosterone levels of the four groups. The groups were designated: high-fit, young aged about 32 (n = 7); high-fit, old aged about 52 (n = 7); low-fit, young (n = 7), and low-fit, old (n = 7). The subjects were selected and grouped according to physical fitness scores obtained using the regression equation of Ismail et al. Serum testosterone was determined by a radioimmunoassay method. The pre-test ANOVA revealed that the high-fit groups had a significantly (p less than .01) higher testosterone level (754.29 ng/100 ml) than the low-fit groups (548.07 ng/100 ml) and the high-fit, young group (925.01 ng/100 ml) was significantly (p less than .01) higher than the other three groups. Post-test values were adjusted using pre-test testosterone values as covariates. No significant differences among the groups were found indicating that the serum testosterone levels were the same regardless of different ages and fitness levels. The findings were discussed in light of physiological, biochemical and psychological factors.

Influence of physical fitness on second- and third-order personality factors using orthogonal and oblique rotations

The study investigated the relationship between physical fitness and personality variables at second- and third-order factor-analytic structures. Further, the stability of the factor structures at pre- and post-physical fitness program tests was examined by orthogonal and oblique rotations. Physical fitness and personality data were collected on 56 middle-aged males. The fitness and personality variables were factor analyzed and rotated orthogonally and obliquely by the principal axis form of solution. As a result, five second-order factors were extracted, both initially and finally. Factor scores were estimated for each S on each of the second-order factors, and data were factor analyzed to extract the third-order factors. The second-order factors closely resembled Cattell's factors, but subtle differences were found to exist between initial and final factor structures that may have been due to the influence of the fitness program. Two third-order factors were extracted initially and three finally when the factor scores were rotated orthogonally and obliquely, and physical fitness was associated with two of these hierarchical factors both initially and finally. The hierarchical factor structures appeared to be comparable to the scales of Eysenck. On the basis of the present findings it was concluded that the problem of rotation was not of importance and scientifically uninteresting and that the hierarchical factor solutions were highly stable. Further, it appears that the hierarchical levels of personality are manifested in two syndromes confounded by "traits" and "states" of personality. These two syndromes are Introversion vs. Extraversion and Neuroticism vs. Stability. The extraction of additional factors, such as Low Superego Strength vs. High Superego Strength, as in this study, is completely dependent upon the treatment or conditions superimposed.

Variability of corticosteroid responses during exercise stress in active and sedentary middle-aged males

Two groups of middle-aged male subjects (both N=11), one active (mean age 44.6 years) and one sedentary (mean age 43.7 years), undertook a graded exercise stress test on a bicycle ergometer in the post-absorptive state. Blood serum corticosteroid levels were measured at the following stages of metabolism; at rest, under conditions of submaximal and "maximal' exercise and during recovery. The active group showed no significant change in mean serum corticosteroid levels from resting values, during exercise and recovery. However the sedentary group displayed a significant increase in mean serum corticosteroid levels from a resting value of 5.81 plus or minus 0.41 mub-g/100 ml. (mean plus or minus S.E.) to 7.83 plus or minus 0.71 mug/100 ml. during "maximal' exercise (p smaller than 0.05), which was maintained throughout recovery 7.82 plus or minus 0.70 ug/100 ml (p smaller than 0.05). Futhermore the active group demonstrated significantly lower mean serum corticosteroid levels compared with the sedentary group under conditions of submaximal (p smaller than 0.05) and "maximal' (p smaller than 0.01) exercise and during recovery (p smaller than 0.01). It was concluded that the variability in the response patterns of serum corticosteroids during exercise stress in active and sedentary middle-aged males, reflected the physiological differences observed between the two groups of subjects.