A PRELIMINARY ANALYSIS OF RESPONSES TO EXERCISE ANCHORED TO VIGOROUS INTENSITY HEART RATES
Djadmann Gustave, Pasquale J. Succi, Brian Benitez, Minyoung Kwak, Jody L. Clasey, FACSM, Kathryn R. Lanphere, Haley C. Bergstrom. University of Kentucky, Lexington, KY.
BACKGROUND: Exercise prescription to improve cardiorespiratory endurance (CE) is often based on percentages of the reserve or maximum heart rate (HRmax). However, no studies have examined the responses to constant HR exercise at the current vigorous intensity recommendations. This study examined the responses to constant HR exercise at the upper (95%HRmax) and lower (77%HRmax) vigorous intensity range and quantified the time spent in the severe (>respiratory compensation point [RCP]), heavy (ventilatory threshold [VT]), and moderate (METHODS: Six subjects (mean±SD age=26.4±4.8yrs, height=170.9±8.9cm, weight=73.5±11.3kg) performed a graded exercise test on a cycle ergometer to determine the maximum volume of oxygen consumption (V̇O2max),HRmax, 77% and 95% HRmax, peak power output (PPO), VT, and RCP. On separate days, subjects performed constant HR trials to exhaustion (or to 60 min, plus the time to reach the HR) at 77% (time to exhaustion [TLim]=51.06±19.12 min, range=25.33-64.67min) and 95% HRmax (TLim=21.17± 11.65min, range =8.00-35.67min) with V̇O2 and power output (P) recorded and normalized to their respective values at PPO in 10% intervals of TLim. Polynomial regression analyses were used to examine the change (positive, negative) and pattern (linear, quadratic) of V̇O2 and P (alpha=0.05). RESULTS: For each subject, the average HR at 77% (144±4 beats·min-1 [b·min-1]) and 95% (177±5 b·min-1) HRmax was maintained within a ±2 b·min-1 for each trial. At 77% HRmax, subjects demonstrated linear (n=2) and quadratic (n=4) decreases in V̇O2 and linear (n=3) and quadratic decreases in P (n=3). Subjects spent an average of 44.71±20.32, 6.33±9.12, and 0.00±0.00 min in the moderate, heavy, and severe intensity domains, respectively. At 95%HRmax, subjects demonstrated linear (n=5) and quadratic (n=1) decreases in V̇O2 and linear (n=4) and quadratic (n=2) decreases in P. Subjects spent an average of 8.06±9.97, 10.22±6.15, and 2.89±2.04 minutes in the moderate, heavy, and severe intensity domains, respectively. CONCLUSIONS: There were decreases in the metabolic cost of exercise that tracked P for exercise anchored to the lower and upper HR. The lower HR may be at an intensity that is too low to maximize the metabolic stimulus (exercise primarily in the moderate domain), while the upper HR may be at an intensity too high to be sustained for the recommended time (20-60min) to improve CE.
Gustave, D; Succi, PJ; Benitez, B; Kwak, M; Clasey, FACSM, JL; Lanphere, KR; and Bergstrom, HC
"A PRELIMINARY ANALYSIS OF RESPONSES TO EXERCISE ANCHORED TO VIGOROUS INTENSITY HEART RATES,"
International Journal of Exercise Science: Conference Proceedings: Vol. 16:
2, Article 344.
Available at: https://digitalcommons.wku.edu/ijesab/vol16/iss2/344