Aging may cause significant changes in human pulmonary dynamics. Age-related changes in pulmonary function are related to both structural and functional factors. These changes include increases in the stiffness of the costovertebral joints and decreased chest wall compliance which induces kyphosis and increases work of breathing (Robergs & Roberts, 1997). Respiratory muscles decrease in resting length causing a decrease in maximal voluntary ventilation (MVV) which can indicate abnormal respiratory mechanics (Robergs & Roberts, 1997). Additionally, weak abdominal muscles may play a role in ventilation during physical activity as they are recruited during heavy breathing (Baechle & Earle, 2008). Lung tissue is altered with aging. There is changes size in the alveoli and alveolar ducts. This leads to a reduced surface area for diffusion and a reduction in supporting tissue for peripheral airways combined coined “senile emphysema” (Rodriguez-Roisin et al., 1999). This causes less effective mixing of air (Rodriguez-Roisin et al., 1999, Baechle & Earle, 2008). A decrease in pulmonary capillaries causes reduced diffusion capacity and alterations in hemoglobin Pa02 saturation (Baechle & Earle, 2008). Finally, systemic inflammation may limit pulmonary function as researchers have found a link between C-reactive protein and declines in forced vital capacity (Shaaban et al., 2006).
So can exercise improve lung function?
Even with all the changes in pulmonary dynamics with aging, in the absence of disease, the respiratory system is able to meet the demands of adequate gas exchange both at rest and during physical activity (Rodriguez-Roisin et al., 1999). Additionally, one cannot fully explain changes in pulmonary function by simply a factor of aging as regular aerobic training can blunt the usual decline in static and dynamic functions (McArdle, Katch, & Katch, 2015).
Changes with aerobic training
Unfortunately, the pulmonary system does not gain significant static lung changes with aerobic exercise (McArdle, Katch, & Katch, 2015). None the less, twenty weeks of aerobic training was found to improve the function of the respiratory muscles (McArdle, Katch, & Katch, 2015). Training of the ventilatory muscles may provide a pay-off as it can increase its strength and endurance thereby improving MVV (McArdle, Katch, & Katch, 2015). Aerobic exercise training can stimulate changes in pulmonary dynamics. During aerobic training, breathing is “fine-tuned” to allow for improved 02 delivery to non-respiratory muscles (McArdle, Katch, & Katch, 2015). After several weeks of aerobic training, a decrease in ventilatory equivalent is observed thereby reducing the total cost of energy needed for breathing (McArdle, Katch, & Katch, 2015). Training increases tidal volume and lowers breathing frequency allowing for greater oxygen extraction from the blood (McArdle, Katch, & Katch, 2015).
Changes with resistance training
Resistance training (RT), particularly high-intensity inspiratory muscle training (IMT), which is commonly used in pulmonary rehab settings has demonstrated promise. A study by Enright et al. looked at IMT in healthy subjects. The subjects trained for 8-weeks at 80% of maximal effort. The participants underwent pre-and post-assessments for body composition, pulmonary function, inspiratory muscle function, and diaphragm thickness and thickening ratio, and exercise capacity. The results demonstrated that that IMT improved exercise capacity, increased diaphragm thickness, and improved lung volumes (Enright, Unnithan, Heward, Withnall, & Davies, 2006). We know that multiple muscles are involved in ventilation such as scapular elevators, spinal erectors, rectus abdominis, posterior serrati muscles, and others (McArdle, Katch, & Katch, 2015) which can be trained via traditional resistance training. In a meta-analysis by Strasser et al., they reviewed 14 randomized control trials and found that resistance training was beneficial. The author’s conclusion was: “Based on findings from the meta-analysis, RT produces a clinically and statistically significant effect on respiratory function (such as forced vital capacity) and is therefore recommended in the management of COPD” (Strasser, Siebert, & Schobersberger, 2012).
Baechle, T. R., & Earle, R. W. (2008). Essentials of strength training and conditioning (3rd ed.). Champaign: Human Kinetics.
Enright, S. J., Unnithan, V. B., Heward, C., Withnall, L., & Davies, D. H. (2006, March 01). Effect of High-Intensity Inspiratory Muscle Training on Lung Volumes, Diaphragm Thickness, and Exercise Capacity in Subjects Who Are Healthy | Physical Therapy | Oxford Academic. Retrieved from https://academic.oup.com/ptj/article/86/3/345/2805157/Effect-of-High-Intensity-Inspiratory-Muscle
Griffith, K., Sherrill, D., Siegel, E., Manolio, T., Bonekat, H., & Enright, P. (2001). Predictors of Loss of Lung Function in the Elderly. American Journal of Respiratory and Critical Care Medicine, 163(1), 61-68. doi:10.1164/ajrccm.163.1.9906089
McArdle, W. D., Katch, F. I., & Katch, V. L. (2015). Exercise physiology: Nutrition, energy, and human performance (8th ed.). Baltimore: Wolters Kluwer Health/Lippincott Williams & Wilkins.
Robergs, R. A., & Roberts, S. (1997). Exercise physiology: Exercise, performance, and clinical applications. St. Louis: Mosby.
Rodriguez-Roisin, R., Burgos, F., Roca, J., BarberÃ , J., Marrades, R., & Wagner, P. (1999). Physiological changes in respiratory function associated with ageing. European Respiratory Journal, 14(6), 1454-1455. doi:10.1183/09031936.99.14614549
Shaaban, R., Kony, S., Driss, F., Leynaert, B., Soussan, D., Pin, I., . . . Zureik, M. (2006). Change in C-reactive protein levels and FEV1 decline: A longitudinal population-based study. Respiratory Medicine, 100(12), 2112-2120. doi:10.1016/j.rmed.2006.03.027
Strasser, B., Siebert, U., & Schobersberger, W. (2012). Effects of resistance training on respiratory function in patients with chronic obstructive pulmonary disease: A systematic review and meta-analysis. Sleep and Breathing, 17(1), 217-226. doi:10.1007/s11325-012-0676-4