Hiking above the threshold to maximize Post-Exercise Hypotension

Purpose: The literature documents the influence of high-intensity exercise, especially above the ventilatory threshold (VT), on blood pressure (BP). The temporary decrease in BP, particularly systolic BP (sBP), following exercise is referred to as Post-Exercise Hypotension (PEH). Despite the benefits of exercise on BP, no study has yet investigated the impact of outdoor activities on PEH. Therefore, the study aimed to investigate the PEH response following hiking and its relationship with the duration spent above the VT (MIN C VT). Methods: The study included one female (F, age: 23 years; body mass: 65 kg; height: 167 cm; BMI 23.3 kg/m2) and one male (M, age: 24 years; body mass: 72 kg; height: 180 cm; BMI: 22.2 kg/m2). To identify the corresponding values of oxygen uptake (VO2) and heart rate (HR) at VT, subjects underwent a submaximal incremental walking test. During the test, participants selected a speed that represented comfortable walking during the first 2-min stage at 0% treadmill grade. Subsequently, the grade was increased by 2% at each stage until 95% of the estimated maximum heart rate (HRmax) was achieved. VT was determined using the v-slope method. Following 24-h of rest, participants underwent a field session involving a selected hike (length * 3800 m). sBP was measured 15-min before (PRE) and 30-min after (POST) the hike. PEH was calculated as the difference between sBP PRE and POST. VO2 and HR were continuously recorded throughout the hike to assess the internal load. Results: The hike was completed in 45: 19 min (MIN C VT = 14 min) by F, while M completed it in 42: 43 min (MIN C VT = 0 min). The average HR for F was 133 ± 15 bpm, corresponding to 68%HRmax, and for M 120 ± 15 bpm corresponding to 62% of HRmax, indicating a light to moderate intensity. The average values of VO2 were 20.2 ± 6.5 ml/kg/min for F (VO2 MIN C VT = 28.2 ± 2.3 ml/kg/min) and 14.5 ± 5.1 ml/kg/min for M. Both individuals exhibited lower sBP values during POST (F: 103 mmHg; M: 117 mmHg) compared to PRE (F: 128 mmHg; M: 130 mmHg), resulting in PEH of 25 mmHg for F and 13 mmHg for M. Conclusions: Despite variations in sBP levels, PEH was observed in both participants. The MIN C VT appeared to play a crucial role in enhancing PEH, particularly in the F participant. These results emphasize the importance of training at high-intensity levels, specifically above the VT, to maximize the sBP reduction following outdoor activities.