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Prescribing aerobic exercise intensity with exercise heart rate as a multiplier of resting heart rate
Author
Koh, Wen Kiat
Supervisor
Balasekaran, Govindasamy
Abstract
Modernization around the world has been associated with changes in people’s lifestyle such as reduced physical activity, which in turn has associated with increased risk of cardiovascular diseases and obesity. High level of cardiorespiratory fitness has an inverse relationship with cardiovascular diseases and obesity, and can be improved through correct prescription of aerobic exercise intensity. Several methods of prescription currently exist such as %V̇O2max, %HRmax, %HRR, %V̇O2R and METs, of which %HRR is one of the most well-validated and widely used method among the rest due to its ability to consider for relative intensity among individuals, and HR is also easy and convenient to measure. However, %HRR requires a complex calculation to derive HRex, and may include errors that arise during the calculation of HRmax and measurement of HRrest, which are components necessary to calculate for HRR. Hence the purpose of this study was to investigate if HRex as a multiplier of HRrest (HRex/HRrest) as a method of prescribing aerobic exercise intensity was comparable to other valid and objective measures of exercise intensity. Twenty male participants, mostly students from NTU and NIE were recruited for the study. Participants had to perform running graded exercise test on a treadmill to maximal exertion, while HR and V̇O2 were measured throughout the test HRrest was also measured by the participants at their homes at first instance upon waking up for three consecutive days. Correlation analysis was performed to compare HRex/HRrest against HR, V̇O2 and exercise intensity as %HRR. Complete data of fifteen participants (age: 24.0 ± 2.6 years; mass: 68.5 ± 9.4 kg; height: 1.7 ± 0.1 m; V̇O2max: 48.3 ± 3.1 ml/kg/min) were considered for analysis. HRex/HRrest revealed a strong positive relationship with V̇O2 (r = .89, p < .01, SEE = 7.5 ml/kg/min), HR (r = .95, p < .01, SEE = 15.4 bpm) and exercise intensity as %HRR (r = .95, p < .01, SEE = 11.8%), and maximal HRex/HRrest value of 3.6 ± 0.5 was found for this group of participants. HR calculated from the HRex/HRrest method was also similar when compared with the well-validated %HRR method, when used with the ‘208 – 0.7(age) HRmax formula across all levels of exercise intensity. However, a fan-shaped relationship was observed between HRex/HRrest and exercise intensity as %HRR, as higher variability of HRex/HRrest was seen with increased intensity of %HRR. In conclusion, prescribing aerobic exercise intensity with HRex/HRrest was supported by the strong correlation with HR, V̇O2 and exercise intensity as %HRR, and HR calculated was similar compared with %HRR method and ‘208 – 0.7(age) HRmax formula. However the HRex/HRrest values derived is only limited to population with similar characteristics as participants of this study, and should be used with caution as a wider range of errors was observed at higher exercise intensity.
Date Issued
2020
Call Number
RA781.15 Koh
Date Submitted
2020