.21.4 Fitness and lung function in young smokers
Young smokers tend to be less physically fit than their non-smoking peers, fitness declining with increasing levels of tobacco consumption.11 The cumulative effects of smoking from a young age on physical performance in midlife was assessed in a large British cohort study with data on smoking history from age 20 (median age at smoking initiation 16 years).17 Researchers found that at age 53, ever-smokers had significantly poorer overall physical performance, balance and chair rising than never smokers, with performance decreasing significantly for every 10 pack-years smoked.17
A study among a cohort of 18–21 year old Finnish males found levels of aerobic fitness to be significantly lower in regular smokers compared with non-smokers (after controlling for physical activity, education and body mass index) and fitness was associated with smoking history.10 A small study among a group of healthy young smokers (mean age 21.4 years) found that smoking was associated with resting and exercise tachycardia, demonstrating significant and acute negative effects on cardiac autonomic function due to smoking both at rest and during exercise. Results suggested that pre-exercise smoking of a single cigarette impaired physiological response to both peak and sub-maximal exercise; this may greatly increase vulnerability to myocardial electrical instability and therefore predispose to higher risk of cardiovascular events.18