Background: The aim of this study was to determine if a 6-week high-intensity interval training (HIIT) protocol with increasing exercise volume affects aerobic capacity and arterial blood pressure (BP) measured during a fatiguing isometric handgrip test (IHT) in middle-aged, normotensive men and to assess whether sprint performance is associated with training-induced changes in BP.
Methods: Fourteen recreationally active men (age 43.0±0.9 years, body mass 74.4±2.1 kg, body height 1.74±0.02 m, BMI 24.7±0.5 kg/m2 [mean±SE]) participated in 12 HIIT sessions at an intensity of 85% of heart rate reserve. Sprinting ability was estimated at baseline using the 50-yard dash test (50YDT). Pre- and post-HIIT aerobic capacity and pressor response was assessed by the 12-min Cooper run test (12CT) and the IHT at 30% of maximal voluntary contraction, respectively.
Results: Following the intervention, the distance covered in the 12CT and handgrip time to fatigue (HTF) significantly increased (P<0.05) but only diastolic BP significantly decreased (P<0.05) compared with pre-HIIT values. Changes (Δ - post- vs. pre-HIIT values) in HTF correlated positively with 50YDT performance (P<0.05). However, significant negative relationships were found between 50YDT and Δ in systolic, diastolic, and mean BP during the IHT except for resting values.
Conclusions: The findings suggest that a HIIT intervention in middle-aged, normotensive men enhances aerobic capacity with a concomitant decrease in DBP and that training-induced ΔBP during IHT are dependent on sprinting ability.