Search

The purpose of this study was to determine whether dyspnea ratings would be similar during submaximal (as used for training) and incremental (as used in testing) exercise at specific intensities in patients with chronic obstructive pulmonary disease (COPD).

MAHLER, DONALD A., BRUCE E. ANDREA, and DONALD C. ANDRESEN. Comparison of 6-min “all-out” and incremental exercise tests in elite oarsmen. Med, Sci. Sports Exerc., Vol. 16, No. 6, pp. 567–571, 1984. A high aerobic capacity is an important criterion for rowing success. Two exercise protocols, the 6-min “all-out” (6M-AO) and progressive incremental (PI) tests, have been used to evaluate physiological performance in rowers and to select team members. We measured heart rate (HR), minute ventilation (VE), oxygen consumption (VO2), and carbon dioxide production (VCO2) every 30 s, and obtained ratings of perceived exertion (RPE) from 12 candidates for the 1983 United States Men's Lightweight Rowing Team. Testing was randomized and each oarsman performed a different test on the rowing ergometer on consecutive days. For the group, age was 23 ± 2 yr (mean ± SD), height was 183 ± 3 cm, and weight was 72.2 ± 1.4 kg. Peak physiological values were achieved in the first 2 min of exercise for the 6M-AO test, but in the last 2 min for the PI test. There were no statistically significant differences among peak values for HR, VE, VO2, VCO2, and RPE with each test. The peak ventilatory equivalent for oxygen (VE/VO2) was also similar. The onset of anaerobic metabolism was observed at 83 ± 4 of peak VO2during the PI test, while anaerobic metabolism has been shown to occur within the first minute of the 6M-AO test. We conclude that physiological values at peak exercise were similar for the 6M-AO and PI tests. Because the onset of anaerobic metabolism can only be determined by noninvasive means using the PI test, this method of testing is preferable for the physiological assessment of rowing performance. The results can be used to assist the coach in selecting team members and in establishing an individual training program.

MAHLER, D. A., B. HUNTER, T. LENTINE, and J. WARD. Locomotor-respiratory coupling develops in novice female rowers with training. Med. Sci. Sports Exerc., Vol. 23, No. 12, pp. 1362–1366, 1991. The purpose of this study was to investigate the hypothesis that locomotor-respiratory coupling (LRC), or entrainment of breathing, develops in the sport of rowing as a result of training. We prospectively evaluated exercise responses over an 8 month training session (October to May) in 12 female subjects who were members of the Dartmouth College novice rowing team. Progressive, incremental exercise testing was performed on the variable-resistance rowing ergometer (Concept II, Morrisville, VT). To relate the pattern of breathing to the mechanics of rowing, the catch and finish of each rowing stroke during the last 30 s of each minute of exercise were marked on the strip chart paper that recorded inspiratory flow measured by using a heated pneumotachograph. Age was 18 ± 1 yr (mean ± SE); weight was 67.5 ± 2.1 kg. Peak oxygen consumption (O2) increased by 10 from October (40.8 ± 0.6 ml kg min-1) to May (P< 0.001). Chi-square goodness-of-fit analysis was used to assess whether the proportion of inspirations occurring in each of four quadrants of circle plots representing repetitive rowing strokes exercise intensities of 100 watts (W) and peak O2were random or corresponded to a regular pattern of breathing. Although 5 of 12 subjects demonstrated LRC at exercise of 100 W in October, there was no significant change at this submaximal intensity over the training season. Only 2 of 12 subjects showed LRC at peak exercise in October, bat there was a significant increase (P= 0.003) in the number of subjects who entrained breathing in Jan (10/12) and May (8/12). A majority of subjects exhibited a 2:1 ratio of breaths per rowing stroke. We conclude that LRC can develop alter an 8 month training program in the sport of rowing, and was most evident at peak exercise intensity.

MAHLER, D. A. Exercise-induced asthma. Med. Sci. Sports Exerc., Vol. 25, No. 5, pp. 554–561, 1993. Bronchoconstriction associated with exercise can occur in nearly all individuals with asthma and in 35–40 of those with allergic rhinitis/hay fever symptoms. This represents approximately 12–15 of the population. Exercise-induced asthma (EIA) is a clinical syndrome characterized by transient airflow obstruction typically 5–15 min after cessation of physical exertion. Symptoms may include chest tightness, breathlessness, coughing, and/or wheezing. Some individuals may experience delayed bronchoconstriction (late phase response) 6–10 h after completing exercise. Approximately 40–50 of those with asthma exhibit a “refractory period”, i.e., diminished bronchoconstriction to exercise performed within 2 h. The pathophysiology of EIA is related to thermal events within the intrathoracic airways. Alterations in the temperature of the airways and/or osmolarity in the epithelial lining fluid cause release of mediators in the airways and the development of bronchoconstriction. Although EIA can be strongly suspected by an appropriate history, pulmonary function testing is necessary to make a specific diagnosis. Measurement of lung function is an important first diagnostic test. If there is no evidence of airflow obstruction at rest, then either bronchoprovocation testing or exercise challenge testing is indicated. Nonpharmacologic therapy includes “warm-up” exercise prior to training or competition to induce a “refractory period” and to prevent/reduce bronchoconstriction. An inhaled beta2-adrenergic agonist, e.g., albuterol, is usually effective for preventing/treating EIA. Cromolyn sodium is an alternative class of medication that inhibits both the early and late phase responses. Other bronchodilator agents are available if combination therapy with an inhaled beta2-adrenergic agonist and cromolyn sodium is not effective. Health care providers should provide education about asthma management as related to EIA.