Cardiovascular response to strength training is more affected by intensity than volume in healthy subjects

Abstract

Objective: To determine and compare the cardiovascular responses to three resistance exercise protocols with different volumes and loads. Methods: The study included 15 healthy subjects, experienced in resistance training, who underwent supine bench press exercise with three different volumes and loads separated by 48 hours, with a crossover model: a) 4 repetitions at 90% of one repetition maximum (4/90%), b) 8 repetitions at 80% of one repetition maximum (8/80%), and c) 15 repetitions at 65% of one repetition maximum (15/65%). Immediately following each protocol, measures of heart rate, systolic and diastolic blood pressure were performed, and were used to calculate the rate pressure product. Results: The 4/90% protocol resulted in an increase in heart rate (Δ = 84.57%; effect size [ES] = 0.31), systolic blood pressure (Δ = 24.03%; ES = 0.42), diastolic blood pressure (Δ = 8.47%; ES = 0.27) and rate pressure product (Δ = 129.65%; ES = 0.54). The 8/80% protocol resulted in changes on: heart rate (Δ = 74.94%; ES = 0.57), systolic blood pressure (Δ = 20.67%; ES = 0.27), diastolic blood pressure (Δ = 6.91%; ES = 0.15) and rate pressure product (Δ = 111.78%; ES = 0.48). The 15/65% protocol resulted in alterations on: heart rate (Δ = 66.77%; ES = 0.39), systolic blood pressure (Δ = 16.85%; ES = 0.35), diastolic blood pressure (Δ = 3.38%; ES = 0.13) and rate pressure product (Δ = 96.41%; ES = 0.30). Increases in all variables pre to post resistance exercise were observed for all protocols (p < 0.05). When comparing the three different protocols, it was found that the heart rate (p < 0.001), systolic blood pressure (p = 0.034) and rate pressure product (p < 0.001), were more elevated in the 4/90% compared to the 15/65%. Conclusion: The bench press exercise performed with low volume and high intensity promotes a more pronounced cardiovascular response compared to the same exercise performed with high volume and low intensity.