Effects of cigarette smoking on cardiac autonomic function during dynamic exercise

Nicotine supplementation enhances simulated game performance of archery athletes

Background

Nicotine is beneficial to mood, arousal and cognition in humans. Due to the importance of cognitive functioning for archery athletes, we investigated the effects of nicotine supplementation on the cognitive abilities, heart rate variability (HRV), and sport performance of professional archers.

Methods

Eleven college archers were recruited and given 2 mg of nicotine supplementation (NIC group) and placebo (PLA group) in a crossover design.

Results

The results showed that at 30 min after the intake of nicotine gum, the “correct rejection” time in the NIC group was significantly lower than that of the PLA group (7.29 ± 0.87 vs. 8.23 ± 0.98 msec, p < 0.05). In addition, the NIC group completed the grooved pegboard test in a shorter time than the PLA group (48.76 ± 3.18 vs. 53.41 ± 4.05 s, p < 0.05), whereas motor reaction times were not different between the two groups. Saliva α-amylase activity was significantly lower after nicotine supplementation (p < 0.01) but increased immediately after the archery test in the NIC group (p < 0.05). In addition, nicotine supplementation significantly decreased HRV and increased the archery score (290.58 ± 10.09 vs. 298.05 ± 8.56, p < 0.01).

Conclusions

Nicotine enhances the performance of archery athletes by increasing cognitive function and stimulating the sympathetic adrenergic system.

The effect of cigarette smoking history on autonomic and cerebral oxygenation responses to an acute exercise bout in smokers

The extent of smoking history is causally linked to adverse cerebro- and cardiovascular health outcomes, while conversely, exercise decreases this risk and associated mortality. However, the acute cerebro- and cardiovascular responses to exercise in smokers are unknown, and may provide insight to understand chronic adaptation. This study examined the acute heart rate (HR) variability (R-R intervals) and cerebral oxygenation responses to exercise in smokers compared to nonsmokers. Fifty-four males classified as smokers (n = 27) or nonsmokers (n = 27) were allocated into either younger (YSM, YNS) or middle-aged groups (MSM, MNS). Participants completed 40 min of stationary cycle ergometry at 50% of VO2peak. Cerebral oxygenation (near-infrared spectroscopy) and autonomic function (HR variability) were collected before, during, and after exercise at 0, 30 min, 1, and 4 hr postexercise. The nonsmoker cohort (MNS and YNS) demonstrated higher values for the standard deviation (SD) of the R-R interval (SDNN) and the root mean squared of the SD at 1 and 4 hr postexercise versus smokers (p < .05). The low frequency (LF) band in YSM was lower than in YNS at 1 hr (p < .05). However, LF and high frequency were higher for MNS compared to MSM at 1 hr (p < .05). Oxygenated hemoglobin during and following exercise were elevated in NS with values for MSM lower than YSM (p < .05). The findings show smoking history can affect cerebral oxygenation during and following an acute exercise bout. Further, following exercise, smokers may exhibit a delay or inhibition in parasympathetic activity.

The Influence of Tobacco Use on Pulmonary Function in Elite Athletes

Objective: We sought to investigate the prevalence of smoking and lung function in the large cohort of elite athletes. Methods: This cross-sectional study included 804 athletes competing at international level who were consecutively examined from January to December 2017. Elite athletes were classified in four groups of sport disciplines (skill, power, endurance and mixed): skill (n = 141), power (n = 107), endurance (n = 105) and mixed sport disciplines (n = 451). All participants underwent pre-participation screening, including spirometry. Results: Study included 745 (92.7%) non-smokers, 20 (2.5%) former smokers and 39 (4.8%) active smokers. The percentage of body fat was higher and the percentage of muscle was lower in active smokers than in non-smokers and former smokers. Active smokers were more prevalent among skill and mixed than in power and endurance sports. FEV1 and FVC, as well as FEV1/FVC ratio, were significantly lower in active smokers than in non-smokers. There was no significant difference in PEF assessed in absolute values and in percentages. Forced expiratory flows, evaluated at the usual intervals (25%, 50% and 75% of FVC), were significantly lower in active smokers than in non-smokers. FEV1 and MEF25 were the lowest among active smokers in the skill sport group, whereas FEV1/FVC, MEF50 and MEF25 were the lowest among active smokers in the power sport group. In mixed and endurance disciplines there was no difference in pulmonary function between non-smokers, former smokers and active smokers. Conclusions: Pulmonary function was reduced in active smokers and these differences were the most prominent in skill and power sports. The percentage of body fat was the highest and percentage of muscle was the lowest in active smokers.

Cardiopulmonary and Muscular Interactions: Potential Implications for Exercise (In)tolerance in Symptomatic Smokers Without Chronic Obstructive Pulmonary Disease

Smoking and physical inactivity are important preventable causes of disability and early death worldwide. Reduced exercise tolerance has been described in smokers, even in those who do not fulfill the extant physiological criteria for chronic obstructive pulmonary disease (COPD) and are not particularly sedentary. In this context, it is widely accepted that exercise capacity depends on complex cardio-pulmonary interactions which support oxygen (O₂) delivery to muscle mitochondria. Although peripheral muscular factors, O₂ transport disturbances (including the effects of increased carboxyhemoglobin) and autonomic nervous system unbalance have been emphasized, other derangements have been more recently described, including early microscopic emphysema, pulmonary microvascular disease, ventilatory and gas exchange inefficiency, and left ventricular diastolic dysfunction. Using an integrative physiological approach, the present review summarizes the recent advances in knowledge on the effects of smoking on the lung-heart-muscle axis under the stress of exercise. Special attention is given to the mechanisms connecting physiological abnormalities such as early cardio-pulmonary derangements, inadequate oxygen delivery and utilization, and generalized bioenergetic disturbances at the muscular level with the negative sensations (sense of heightened muscle effort and breathlessness) that may decrease the tolerance of smokers to physical exercise. A deeper understanding of the systemic effects of smoking in subjects who did not (yet) show evidences of COPD and ischemic heart disease - two devastating smoking related diseases - might prove instrumental to fight their ever-growing burden.

Comparative study of cardiac autonomic status by heart rate variability between under-treatment normotensive and hypertensive known type 2 diabetics

Background

Co-existence of hypertension is known in three quarter of Indian type 2 diabetics, this duo having adverse additive effect on cardiovascular health including dysautonomia. Latter can be measured by simple 5 min heart rate variability (HRV) using simple electrocardiogram, which if reduced indicates cardiac risk.

Objective

We compared HRV parameters between hypertensive and normotensive type 2 diabetics, looking for significant difference if any.

Materials and methods

98 hypertensive and 40 normotensive type 2 diabetics treated as outpatients were evaluated for disease control and risk stratification. Five min resting HRV was measured by Variowin HR, software based instrument, using standard protocols to record time domain, frequency domain and Poincare plot parameters. They were compared between groups for difference.

Results

Mean age was 56 and 51 years, duration 6 years and 4 years respectively in hypertensive (HT) and normotensive (NT) group of type 2 diabetics, which did not significantly differ in distribution of risk factors. There was poor glycaemic control (one third) in both groups and good pressure control in HT group. Both groups revealed all reduced HRV parameters with significant difference in-between only for LF/HF ratio (1.29 in HT vs 2.61 in NT group).

Conclusion

Our findings of HRV suggest that in type 2 diabetics with poor glycaemic and good pressure control, hypertension as a co-existing factor does not make significant difference in cardiac dysautonomia emphasizing residual risk despite antihypertensive treatment and need for early HRV screening, strict glycaemic control and other interventions.

Cerebral oxygenation and sympathetic responses to smoking in young and middle-aged smokers

This study examined the effects of acute tobacco smoking on cerebral oxygenation and autonomic function in 28 male, habitual smokers of shorter young smokers (YSM) or longer middle-aged smokers (MSM) smoking history. Following baseline testing, participants undertook a smoking protocol involving the consumption of two cigarettes within 15 min. Measures of cerebral oxygenation and autonomic function were collected before, during, and 0 min, 30 min, 1 h, and 4 h post-smoking. Tissue saturation index (TSI) for MSM was greater than YSM during cigarette consumption ( p < 0.05). Moreover, MSM observed significant within-group changes for TSI during and post-cigarette consumption ( p < 0.05). Further, MSM observed an increase in low frequency (LF) band from 30 min to 1 h post-consumption, followed by a decline, whereas elevations above MSM were observed in YSM at 4 h ( p < 0.05). Both MSM and YSM showed a decrease in high-frequency (HF) band post-cigarette, while increased LF/HF ratio post-consumption was observed in YSM. A decline in the standard deviation of RR intervals, post-cigarette consumption was evident in MSM ( p < 0.05). Moreover, the root mean square of RR interval in both groups similarly decreased following cigarette consumption ( p < 0.05). Acute smoking affects heart rate variability, suggestive of vagal withdrawal, and maybe indicate an effect of smoking history. Additionally, prolonged smoking history alters cerebral microcirculatory responses to acute tobacco exposure in MSM.

Autonomic Recovery Is Delayed in Chinese Compared with Caucasian following Treadmill Exercise

Caucasian populations have a higher prevalence of cardiovascular disease (CVD) when compared with their Chinese counterparts and CVD is associated with autonomic function. It is unknown whether autonomic function during exercise recovery differs between Caucasians and Chinese. The present study investigated autonomic recovery following an acute bout of treadmill exercise in healthy Caucasians and Chinese. Sixty-two participants (30 Caucasian and 32 Chinese, 50% male) performed an acute bout of treadmill exercise at 70% of heart rate reserve. Heart rate variability (HRV) and baroreflex sensitivity (BRS) were obtained during 5-min epochs at pre-exercise, 30-min, and 60-min post-exercise. HRV was assessed using frequency [natural logarithm of high (LnHF) and low frequency (LnLF) powers, normalized high (nHF) and low frequency (nLF) powers, and LF/HF ratio] and time domains [Root mean square of successive differences (RMSSD), natural logarithm of RMSSD (LnRMSSD) and R-R interval (RRI)]. Spontaneous BRS included both up-up and down-down sequences. At pre-exercise, no group differences were observed for any HR, HRV and BRS parameters. During exercise recovery, significant race-by-time interactions were observed for LnHF, nHF, nLF, LF/HF, LnRMSSD, RRI, HR, and BRS (up-up). The declines in LnHF, nHF, RMSSD, RRI and BRS (up-up) and the increases in LF/HF, nLF and HR were blunted in Chinese when compared to Caucasians from pre-exercise to 30-min to 60-min post-exercise. Chinese exhibited delayed autonomic recovery following an acute bout of treadmill exercise. This delayed autonomic recovery may result from greater sympathetic dominance and extended vagal withdrawal in Chinese.

TRIAL REGISTRATION

Chinese Clinical Trial Register ChiCTR-IPR-15006684.

Immediate Effects of Smoking on Cardiorespiratory Responses During Dynamic Exercise: Arm Vs. Leg Ergometry

Purpose: This study compared the immediate effects of smoking on cardiorespiratory responses to dynamic arm and leg exercises.

Methods:This randomized crossover study recruited 14 college students. Each participant underwent two sets of arm-cranking (AC) and leg-cycling (LC) exercise tests. The testing sequences of the control trial (participants refrained from smoking for 8 h before testing) and the experimental trial (participants smoked two cigarettes immediately before testing) were randomly chosen. We observed immediate changes in pulmonary function and heart rate variability after smoking and before the exercise test. The participants then underwent graded exercise tests of their arms and legs until reaching exhaustion. We compared the peak work achieved and time to exhaustion during the exercise tests with various cardiorespiratory indices [i.e., heart rate, oxygen consumption (VO₂), minute ventilation (V_E)]. The differences between the smoking and control trials were calculated using paired t-tests. For the exercise test periods, VO₂, heart rate, and V_E values were calculated at every 10% increment of the maximal effort time. The main effects of the time and trial, as well as their trial-by-time (4 × 10) interaction effects on the outcome measures, were investigated using repeated measure ANOVA with trend analysis.

Results: 5 min after smoking, the participants exhibited reduced forced vital capacities and forced expiratory volumes in the first second (P < 0.05), in addition to elevated resting heart rates (P < 0.001). The high-frequency, low-frequency, and the total power of the heart rate variability were also reduced (P < 0.05) at rest. For the exercise test periods, smoking reduced the time to exhaustion (P = 0.005) and the ventilatory threshold (P < 0.05) in the LC tests, whereas no significant effects were observed in the AC tests. A trend analysis revealed a significant trial-by-time interaction effect for heart rate, VO₂, and V_E during the graded exercise test (all P < 0.001). Lower VO₂ and V_E levels were exhibited in the exercise response of the smoking trial than in those of the control LC trials, whereas no discernable inter-trial difference was observed in the AC trials. Moreover, the differences in heart rate and V_E response between the LC and AC exercises were significantly smaller after the participants smoked.

Conclusion: This study verified that smoking significantly decreased performance and cardiorespiratory responses to leg exercises. However, the negative effects of smoking on arm exercise performance were not as pronounced.

COMPARAÇÃO DA MODULAÇÃO AUTONÔMICA CARDÍACA DURANTE ESFORÇO DE FUMANTES E NÃO FUMANTES

Introdução O tabagismo é uma das principais causas de morbimortalidade em todo o mundo. Indivíduos fumantes têm risco aumentado de desenvolver disfunção autonômica, a qual pode ser avaliada tanto pela variabilidade da frequência cardíaca (VFC) como pela frequência cardíaca de recuperação (FCRec). A maioria dos estudos envolvendo esta análise é realizada em adultos de idade avançada e na condição de repouso. Objetivos Comparar a atividade autonômica cardíaca em repouso e esforço, em homens jovens, fumantes e não fumantes. Métodos Trinta e dois jovens voluntários, (idade 22,0 ± 2,8 anos) foram distribuídos em dois grupos: o grupo fumante (GF; n=15) e o não fumante (GNF; n=17). Realizou-se o teste de Cooper, com análise da VFC pelo cardiofrequencímetro Polar(r)s810i, em repouso e durante o esforço e FCRec. Resultados No GF, 73% foram classificados com nível de dependência nicotínica "muito baixa" segundo questionário de Fargeström. A classificação de ativos e muito ativos pelo questionário IPAQ correspondeu a mais de 50% da amostra em ambos os grupos. Não se observou diferenças significativas entre os grupos na VFC, tanto no repouso quanto no esforço. Entretanto, em cada grupo, notou-se diferença na maioria dos índices de VFC do repouso para o esforço. No teste de Cooper não foram observadas diferenças significativas na FCmédia, FCpico e de FCRec entre os grupos, mas notou-se uma melhor capacidade funcional no GNF pela distância caminhada (2050,2 ± 300,0 vs. 1780,3 ± 390,4 m, p=0,036). Conclusão O GF apresentou menor capacidade funcional e ativação parassimpática durante o esforço, além de menores índices de VFC durante repouso, o que pode sugerir um comprometimento precoce na modulação autonômica cardíaca.

Effects of nicotine withdrawal on panic-like response to breath holding: a placebo-controlled, double-blind, crossover patch study

BACKGROUND

Cigarette smoking may increase the likelihood of developing panic disorder. Periods of nicotine withdrawal, in particular, may promote panic in individuals high in anxiety sensitivity. We examined the importance of nicotine withdrawal in the occurrence of smoking and panic.

METHODS

We utilized a placebo-controlled, double-blind, randomized, crossover design. Fifty smokers underwent a breath-holding (BH) challenge after the transdermal administration of nicotine on one test day and a placebo on another test day. Physiological and psychological variables were assessed at baseline as well as directly before and after the challenges.

RESULTS

Nicotine abstinence induced a decrease in heart rate and systolic blood pressure (BP) before the BH procedure (heart rate: 78.80 ± 11.43 under nicotine, 70.88 ± 10.83 under placebo; systolic BP: 124.90 ± 11.34 under nicotine, 121.18 ± 13.44 under placebo) and shorter BH duration relative to the nicotine patch condition. Nicotine abstinence did not, though, increase fear reactivity to the challenge.

CONCLUSIONS

The findings for heart rate and BP are consistent with the stimulant properties of nicotine. The reduced capacity to maintain apnea under placebo might be due to carbon dioxide (CO2 ) hypersensitivity during periods of nicotine abstinence. The negative findings regarding fear reactivity might be due to BH being a relatively weak anxiogen. Future researchers are encouraged to employ CO2 -inhalation procedures to study the relationship between nicotine withdrawal and panic.

The effects of cigarette smoking on aerobic and anaerobic capacity and heart rate variability among female university students

Aim

In this study, the effects of cigarette smoking on maximal aerobic capacity, anaerobic capacity, and heart rate variability among female university students were investigated.

Materials and methods

Twelve smokers and 21 nonsmokers participated in this study. All participants performed an intermittent sprint test (IST) and a 20 m shuttle run test to measure their anaerobic capacity and maximal aerobic capacity. The IST was comprised of 6 × 10-second sprints with a 60-second active recovery between each sprint. Heart rate variability was recorded while the participants were in a supine position 20 minutes before and 30 minutes after the IST.

Results

The total work, peak power, and heart rate of the smokers and nonsmokers did not differ significantly. However, the smokers’ average power declined significantly during sprints 4 to 6 (smokers versus nonsmokers, respectively: 95% confidence interval =6.2–7.2 joule/kg versus 6.8–7.6 joule/kg; P<0.05), and their fatigue index increased (smokers versus nonsmokers, respectively: 35.8% ± 2.3% versus 24.5% ± 1.76%; P<0.05) during the IST. The maximal oxygen uptake of nonsmokers was significantly higher than that of the smokers (P<0.05). The standard deviation of the normal to normal intervals and the root mean square successive difference did not differ significantly between nonsmokers and smokers. However, the nonsmokers exhibited a significantly higher normalized high frequency (HF), and significantly lower normalized low frequency (LF), LF/HF ratio, and natural logarithm of the LF/HF when compared with those of the smokers (P<0.05).

Conclusion

Smoking may increase female smokers’ exercise fatigue and decrease their average performance during an IST, while reducing their maximal aerobic capacity. Furthermore, smoking reduces parasympathetic nerve activity and activates sympathetic cardiac control.

Exercise-based smoking cessation interventions among women

Although smoking rates are lower among women than men, women are less likely to quit smoking in cessation trials. This is in part due to their tendency to smoke to help prevent or mitigate negative mood/affect, depression and/or postcessation weight gain. Exercise helps to alleviate women's fear of postcessation weight gain and reduces their cessation-related mood symptoms, making it a theoretically ideal smoking cessation intervention for women. In addition, short bouts of exercise decrease cigarette cravings and withdrawal symptoms among temporarily abstinent smokers. However, results from exercise-based smoking cessation interventions to date have been mostly nonsignificant. This paper describes the theoretical mechanisms (psychological, behavioral, physiological and neurobiological) and practical reasons underlying our belief that exercise-based smoking cessation interventions should not yet be abandoned despite their current paucity of supporting evidence. It also presents ideas for modifying future exercise-based smoking cessation interventions to increase adherence and, as a result, more accurately evaluate the effect of exercise on smoking cessation.