Acute Caffeine Intake Reduces Perceived Exertion But Not Muscle Pain during Moderate Intensity Cycling Exercise in Women with Fibromyalgia

OBJECTIVE

Exacerbated perceived exertion and muscle pain responses during exercise might limit physical activity practice in fibromyalgia patients. Thus, nutritional strategies that can reduce perceived exertion and muscle pain during exercise in fibromyalgia patients would be useful. The purpose of this study was to investigate the effects of acute caffeine intake on the perceptions of exertion and muscle pain during a moderate intensity exercise in women with fibromyalgia.Method: Using a randomized, double-blinded, placebo-controlled and crossover experimental design, eleven sedentary women diagnosed with fibromyalgia (age: 44.6 ± 10.5 years; body mass index: 28.5 ± 4.5 kg.m^-2) ingested a capsule containing either caffeine (5 mg per kg of body mass) or cellulose (placebo), 60 minutes before performing a 30-minute constant-load cycling exercise, with work rate fixed at 50% of their individual peak workload attained in an incremental exercise test. Ratings of perceived leg muscle pain and perceived exertion were assessed every 5 minutes of exercise.Results: The perceived leg muscle pain was similar (F_(1,10) = 1.18, p = 0.30, ŋ² = 0.11) between caffeine (2.1 ± 1.2 arbitrary units) and placebo conditions (2.2 ± 0.9 arbitrary units). The perceived exertion, however, was on average 8 ± 6% lower (F_(1,10) = 12.13; p = 0.006; ŋ² = 0.55) during exercise in the caffeine condition (12.4 ± 1.3 arbitrary units) than in the placebo condition (13.1 ± 1.1 arbitrary units).Conclusions: These findings indicate that acute caffeine intake could be an attractive strategy to attenuate the exacerbated perceived exertion of fibromyalgia patients during moderate intensity exercise.

Individual and interpersonal correlates of cardiorespiratory fitness in adults - Findings from the German Health Interview and Examination Survey

Cardiorespiratory fitness (CRF) is an established predictor of adverse health outcomes. The aim of this study is to investigate potential behavioral, interpersonal and socioeconomic correlates of CRF among men and women living in Germany using data from a population-based nationwide cross-sectional study. 1,439 men and 1,486 women aged 18-64 participated in the German Health Interview and Examination Survey (2008-2011) and completed a standardized sub-maximal cycle ergometer test. Maximal oxygen consumption ([Formula: see text]) in ml·min-1·kg-1 was estimated. Mean values of VO2max for various anthropometric, behavioral, interpersonal, and sociodemographic variables were estimated. Linear regression analyses using multiple imputations technique for missing values was performed to analyze the influence of potential correlates on CRF. Women with high alcohol consumption had higher [Formula: see text], (β = 2.20; 95% CI 0.98 to 3.42) than women with low alcohol consumption and women with high occupational status had higher [Formula: see text] (β = 1.83; 95% CI 0.21 to 3.44) in comparison to women with low occupational status. Among men, high fruit intake (β = 1.52; 95% CI 0.63 to 2.40), compared to low or medium fruit intake and performing at least 2.5 hours of total PA per week (β = 2.19; 95% CI 1.11 to 3.28), compared to less than 2.5 hours was associated with higher [Formula: see text]. Among both men and women, lower body mass index, lower waist circumference and higher levels of physical exercise were considerably associated with higher [Formula: see text]. Among women, those in higher age groups showed a considerably lower level of [Formula: see text] compared with those aged 18-24. Furthermore, mean estimated [Formula: see text] was higher among men (36.5; 95% CI 36.0 to 37.0) than among women (30.3; 95% CI 29.8 to 30.7). Despite the cross-sectional nature of the current study, we conclude that several behavioral, anthropometric, and sociodemographic factors are associated with CRF in the general adult population in Germany. These results can provide evidence to tailor prevention measures according to the needs of specific subgroups.

Correlates and Determinants of Cardiorespiratory Fitness in Adults: a Systematic Review

Background

Enhanced cardiorespiratory fitness (CRF) is now a well-established predictor of numerous adverse health outcomes. Knowledge about the pathways leading to enhanced CRF is essential for developing appropriate interventions. Hence, the aim of this review was to provide a detailed overview of the current state of research regarding individual factors associated with or influencing CRF among the general adult population.

Methods

We searched the PubMed, EMBASE, and Cochrane Library databases and also conducted a search for grey literature (Google Scholar). Eligible indicators of CRF were objectively assessed measures of CRF by submaximal or maximal exercise testing measured using treadmill or cycle ergometer tests. We included quantitative observational studies of the general adult population. Using a semi-quantitative approach, we compiled summary tables aggregating the study results for each potential correlate or determinant of CRF.

Results

We identified 3005 studies, 78 of which met the inclusion criteria. Almost all of these studies were conducted in high-income countries. Study quality scores assessing the risk of bias in the individual studies ranged from 40 to 100%. Male sex, age (inverse), education, socioeconomic status, ethnicity, body mass index (inverse), body weight (inverse), waist circumference, body fat (inverse), resting heart rate (inverse), C-reactive protein (inverse), smoking (inverse), alcohol consumption, and multiple measures of leisure-time physical activity were independently and consistently associated with CRF.

Conclusions

In synthesizing the current research on the correlates and determinants of CRF among adults, this systematic review identified gaps in the current understanding of factors influencing CRF. Beyond the scope of this review, environmental and interpersonal determinants should be further investigated.

Systematic Review Registration

PROSPERO, CRD42017055456.

Electronic supplementary material

The online version of this article (10.1186/s40798-019-0211-2) contains supplementary material, which is available to authorized users.

Caffeine Ingestion With or Without Low-Dose Carbohydrate Improves Exercise Tolerance in Sedentary Adults

Caffeine (CAF) and carbohydrate (CHO) ingestion delay fatigue during prolonged exercise; however, this is primarily documented in endurance trained (ET) athletes. Our purpose was to determine if these ergogenic aids are also effective to improve exercise tolerance in age-matched sedentary (SED) adults. Using a double-blind crossover design, ET and SED (n = 12 each group) completed four exercise trials consisting of 30 min cycling at standardized matched work rates 10% below lactate threshold (MOD-EX) followed by a time to fatigue (TTF) ride at individually prescribed intensity of 5% above lactate threshold. After standardized breakfast, the following drink treatments were given before and throughout exercise: CAF (3 mg/kg of body mass, equivalent to 1.5 cups premium brewed coffee), low calorie CHO (LCHO) (0.4% solution, 2 g total CHO), CAF+LCHO, and artificially-sweetened placebo (PLA). SED and ET had similar perceived exertion (RPE) during MOD-EX and TTF (23.8 ± 3.1 and 24.1 ± 2.6 min in ET, SED, respectively). LCHO did not benefit exercise tolerance compared to PLA and was less effective (p < 0.05) compared to CAF+LCHO for all participants combined. Thus, the two CAF treatments were averaged, resulting in ~5% lower RPE (p < 0.05) and 21% longer TTF (26.3 ± 10.4 min) compared to the no-CAF (21.7 ± 9.9 min) treatments. Blood glucose and lactate were higher (p < 0.05) with CAF vs. no-CAF. SED and ET only differed in metabolic oxidation rates during exercise (higher overall fat oxidation with ET compared to SED). CAF reduces the perceived effort during exercise and increases the capacity for sedentary individuals, as well as trained athletes, to tolerate higher intensity exercise for greater duration; and, these benefits were not further enhanced by ingesting doses of low carbohydrate regularly during exercise.