RT Journal Article
SR Electronic
T1 Heart rate and exercise intensity during training: observations from the DREW Study
JF British Journal of Sports Medicine
JO Br J Sports Med
FD BMJ Publishing Group Ltd and British Association of Sport and Exercise Medicine
SP 750
OP 755
DO 10.1136/bjsm.2008.046342
VO 43
IS 10
A1 Mikus, C R
A1 Earnest, C P
A1 Blair, S N
A1 Church, T S
YR 2009
UL http://bjsm.bmj.com/content/43/10/750.abstract
AB Objective: Cardiovascular drift (CVdrift) is characterised by a continuous, gradual increase in heart rate (HR) after ∼10 min of moderate-intensity aerobic exercise, despite maintenance of a constant work rate. This has important implications for trials that employ HR to monitor exercise intensity, as reducing work rate in order to keep HR constant could result in participants exercising below the intended intensity. Utilising the Dose Response to Exercise in Women (DREW) database, we sought to determine if increases in HR during exercise (CVdrift) resulted in clinically significant reductions in exercise work rate in order to keep HR within a target range. Design: Randomised, prospective study. Setting: DREW clinical exercise trail, The Cooper Institute, Dallas, Texas. Participants: Overweight (body mass index 25–43 kg/m2), previously sedentary postmenopausal women (n  =  326). Intervention: Treadmill and cycling exercise (30–90 min, three to five times per week) at a HR corresponding to 50% of peak oxygen uptake (Vo2peak). Main outcome measure: Changes in exercise intensity (metabolic equivalents (METS)) during exercise in response to CVdrift. Results: We observed small increases in HR (1–4 beats per minute, p<0.001) combined with small increases in intensity (0.01–0.03 METS, p<0.03) during the combined 12 963 exercise training sessions. Further, we identified only 101 (0.78%) sessions in which intensity was reduced during the course of the exercise session, potentially in response to CVdrift. Conclusions: We conclude that CVdrift did not contribute to significant reductions in exercise intensity in the DREW study.