Smoking can contribute to the functional decline of elderly individuals, negatively impacting cellular integrity and cardiorespiratory function. Thus, prolonged exposure to harmful cigarette substances may accelerate the decline in functional capacities. Investigating the association between smoking duration and these markers can provide a better understanding of the impacts of smoking on cell healthy and cardiorespiratory capacity.

To investigate the association between smoking duration, phase angle, oxygen consumption (VO2 peak), and forced vital capacity (FVC) in elderly smokers.

This is a cross-sectional study conducted with elderly smokers of conventional cigarettes who had been smoking for at least one year, of both sexes, aged 60 years or older, capable of walking without assistance, and understanding the instructions for tests and questionnaires. Body composition was measured with tetrapolar bioimpedance and cardiorespiratory capacity through the cardiopulmonary exercise test (CPET) using ramp protocol. Statistical analysis was performed using Jamovi 2.6.26 software. Linear regression was conducted to analyze the associations between variables, with a significant level of p < 0.05.

Eight individuals (62.5% males, 66.2 ± 14.3) years presents body max index of 26.5 ± 3.6 kg/m². The average smoking duration was 47.3250 ± 6.923 years, and the average tobacco load was 34.700 ± 29.5477 packs/year. In body composition and CPET assessments, the phase angle was 5.775 ± 0.465, which is considered borderline for this population and may indicate compromised cellular integrity due to smoking. The FVC was 2.751 ± 0.706 liters, and the relative VO2 peak was 20.913 ± 5.515 ml/min/kg. Linear regression analysis indicated that smoking duration was associated with a reduction in relative VO2 peak (ß = -0.613; 95% CI: -1.408 to -0.131; p = 0.026), explaining 59% of the VO2 peak variation (R² = 0.592). There was no statistically significant association between smoking duration and phase angle (p = 0.996) or FVC (p = 0.924).

Smoking duration was inversely associated with VO2 peak, suggesting a negative impact of chronic smoking on cardiorespiratory capacity. Although no significant association was found with phase angle, the observed values indicate a possible compromise of cellular integrity. Studies with larger samples and considering other outcomes, such as body composition, may provide a deeper understanding of the mechanisms by which smoking affects the functionality of elderly individuals.

Cardiorespiratory decline is associated with a higher risk of morbidity and mortality in the elderly. Therefore, cessation strategies should be initiated early and associated with cardiorespiratory rehabilitation programs. These findings highlight the importance of monitoring functional capacity in elderly smokers.