A multi-trial, retrospective analysis of the antihypertensive effects of high-resistance, low-volume inspiratory muscle strength training

Above-normal blood pressure (BP) is a primary risk factor for cardiovascular diseases. In a retrospective analysis of five pilot trials, we assessed the BP-lowering effects of high-resistance inspiratory muscle strength training (IMST) in adults aged 18-82 years and the impact of IMST on maximal inspiratory pressure (PIMAX), a gauge of inspiratory muscle strength and independent disease risk factor. Participants were randomized to high-resistance IMST (75% PIMAX) or low-resistance sham (15% PIMAX) training (30 breaths/day, 5-7 days/wk, 6 wk). IMST (n = 67) reduced systolic BP (SBP) by 9 ± 6 mmHg (P < 0.01) and diastolic BP (DBP) by 4 ± 4 mmHg (P < 0.01). IMST-related reductions in SBP and DBP emerged by week 2 of training (-4 ± 8 mmHg and -3 ± 6 mmHg; P ≤ 0.01, respectively) and continued across the 6-wk intervention. SBP and DBP were unchanged with sham training (n = 61, all P > 0.05). Select subject characteristics slightly modified the impact of IMST on BP. Greater reductions in SBP were associated with older age (β = -0.07 ± 0.03; P = 0.04) and greater reductions in DBP associated with medication-naïve BP (β = -3 ± 1; P = 0.02) and higher initial DBP (β = -0.12 ± 0.05; P = 0.04). PIMAX increased with high-resistance IMST and low-resistance sham training, with a greater increase from high-resistance IMST (+20 ± 17 vs. +6 ± 14 cmH2O; P < 0.01). Gains in PIMAX had a modest inverse relation with age (β = -0.20 ± 0.09; P = 0.03) and baseline PIMAX (β = -0.15 ± 0.07; P = 0.04) but not to reductions in SBP or DBP. These compiled findings from multiple independent trials provide the strongest evidence to date that high-resistance IMST evokes clinically significant reductions in SBP and DBP, and increases in PIMAX, in adult men and women.NEW & NOTEWORTHY In young-to-older adult men and women, 6 wk of high-resistance inspiratory muscle strength training lowers casual systolic and diastolic blood pressure by 9 mmHg and 4 mmHg, respectively, with initial reductions observed by week 2 of training. Given blood pressure outcomes with the intervention were only slightly altered by subject baseline characteristics (i.e., age, blood pressure medication, and health status), inspiratory muscle strength training is effective in lowering blood pressure in a broad range of adults.

Effects of three low-volume, high-intensity exercise conditions on affective valence

A common barrier to exercise is "lack of time". Accordingly, interest in low-volume, high-intensity training has grown exponentially since this activity is considered time-efficient. However, the high-intensity nature of this exercise may frequently result in feelings of displeasure creating another barrier for many people. The purpose of this study was to compare affective (pleasure-displeasure) responses to three low-volume, high-intensity exercise conditions, including a novel shortened-sprint protocol. Using a within-subjects, randomised crossover experiment, healthy participants (N = 36) undertook a single bout of: 1) traditional reduced-exertion, high-intensity interval training (TREHIT), 2) a novel, shortened-sprint REHIT (SSREHIT) protocol, and 3) sprint continuous training (SCT). Affect and perceived efforts were recorded throughout exercise using the Feeling Scale (FS) and the 15-point Borg Rating of Perceived Exertion (RPE) scale, respectively. Enjoyment was recorded 5 min post-exercise using the Exercise Enjoyment Scale (EES). Differences were found for FS (condition by time interaction: P = 0.01_GG, η² = 0.26), RPE (P = 0.01_GG, η² = 0.23), and enjoyment (P < 0.01) with all outcomes favouring SSREHIT. Shortened-sprint protocols may diminish feelings of displeasure and might be a time-efficient yet tolerable exercise choice to help motivate some people to increase their physical activity and fitness.

The efficacy of a whole body sprint-interval training intervention in an office setting: A feasibility study

BACKGROUND

Whole body sprint-interval training (WB-SIT) represents a mode of exercise training that is both time-efficient and does not require access to an exercise facility.

OBJECTIVE

The current study examined the feasibility of implementing a WB-SIT intervention in a workplace setting.

METHODS

A total of 747 employees from a large office building were invited to participate with 31 individuals being enrolled in the study. Anthropometrics, aerobic fitness, core and upper body strength, and lower body mobility were assessed before and after a 12-week exercise intervention consisting of 2-4 training sessions per week. Each training session required participants to complete 8, 20-second intervals (separated by 10 seconds of rest) of whole body exercise.

RESULTS

Proportion of participation was 4.2% while the response rate was 35% (11/31 participants completed post training testing). In responders, compliance to prescribed training was 83±17%, and significant (p < 0.05) improvements were observed for aerobic fitness, push-up performance and lower body mobility.

CONCLUSION

These results demonstrate the efficacy of WB-SIT for improving fitness and mobility in an office setting, but highlight the difficulties in achieving high rates of participation and response in this setting.