Trained Vs Untrained Hr And Bp Responses To High Intensity Resistance Exercise

Abstract

Recently, high intensity (80% of 1 RM) resistance exercise (RE), in particular, has been shown to elicit post exercise hypotension (PEH) in normotensive individuals during separate upper and lower body training sessions (Simoes et al., 2004). It remains unclear whether PEH occurs in resistance trained (T) and untrained (UT) normotensive. PURPOSE To examine heart rate (HR) and blood pressure (BP) response during and after combined upper and lower body RE in resistance trained (continuous training for at least 6 weeks) and untrained (UT) normotensives. METHODS After 1 RM determination for bench press (BPr), leg press (LP), shoulder press, biceps curl, triceps pushdown (TP), lat pulldown, and leg curl (LC), ten T and ten UT college aged volunteers performed two sets of 8 to 10 RM at 75% of 1RM for each exercise in the above order. Two minutes rest was given between sets and different exercises with HR and BP recorded after the second set for upper body (BPr), lower body (LP) and the smaller accessory muscle groups (TP and LC). HR and BP were also recorded in the seated position at 10-minute intervals during recovery for 1 hour. RESULTS Trained subjects had a significantly (p<.05) greater 1 RM compared to UT for each of the exercises with the greatest differences in the lower extremity (LP: 538.6 ± 154.3 vs. 400.1 ± 78.4 lb) and the smallest difference in the triceps (TP: 104.5 ± 26.1 vs. 80.5 ± 16.4 lb). HR responses were not significantly (p>.05) different between UT and T groups for any of the measurement times. The highest HR occurred following LP in UT (159 ±11.1 bpm) and TP (161.2 ± 10.9 bpm) in the T. HR response for LP in T was 158 ± 16.6 bpm. Systolic BP was not significantly (p>.05) different for any of the measurement times between groups although within groups it was significantly (p<.05) different in response to the exercises (LP vs. LC for T: 142 ± 19.6 vs 117.2 ± 15.8 mmHg; LP vs. BP for UT: 145 ± 15.8 vs. 131.2 ± 10.8 mmHg). PEH was evident in both UT (mean ± SD =22 ± 6.6 mmHg drop in SBP from rest, n=7) and T (mean ± SD =24 ± 9.5 mmHg drop from rest, n=4). CONCLUSIONS Based on these results, PEH appears more common in UT than trained but still occurs in the trained. We speculate that short rest periods repeated over the course of a resistance training program contribute to PEH due to compromised vasoregulation.