Can systemic myokine response to an acute exercise bout predict high and low responders to resistance training?

Acute physical exercise and ambulatory blood pressure in resistant hypertension

OBJECTIVES

The effects of acute physical exercise in patients with resistant hypertension remain largely unexplored compared with hypertensive patients in general. We assessed the short-term effects of acute moderate-intensity (MICE) and high-intensity interval exercise (HIIE) on the clinic (BP) and 24-h ambulatory blood pressure (ABP) of patients with resistant hypertension.

METHODS

Using a crossover randomized controlled design, 10 participants (56 ± 7 years) with resistant hypertension performed three experimental sessions: MICE, HIIE, and control. MICE consisted of continuous treadmill exercise at an intensity of 3-4 metabolic equivalents of energy (METs) until completing 3 kcal/kg and was energy-matched to HIIE (which included six to eight intervals of 3 min duration at 6-7 METs interspersed with 1.5-min rests at 3 METs). In the control session, participants remained seated for 50 min. Flow-mediated vasodilation, autonomic nervous system balance (heart rate variability), exerkines [interleukin (IL)-6, IL-8, IL-15, vascular endothelial growth factor A, irisin, adiponectin, and angiopoietin] and 71 inflammatory-related proteins were also measured.

RESULTS

Compared with baseline, HIIE and MICE reduced clinic SBP immediately ( P  < 0.001 for both) and 90 min ( P  = 0.001 and P  = 0.041, respectively) postexercise. HIIE and MICE also reduced clinic DBP immediately postexercise ( P  = 0.003 and P  = 0.025). By contrast, no changes were found in the control session. On the other hand, no significant effects were noted for 24 h ABP measures or for the rest of variables.

CONCLUSION

Although in patients with resistant hypertension, acute aerobic exercise induces short-term reductions in clinic BP, this stimulus does not suffice to reduce 24 h ABP or to impact on potential biological mechanisms.

Stubborn Exercise Responders-Where to Next?

There is a wide variance in the magnitude of physiological adaptations after resistance or endurance training. The incidence of “non” or “poor” responders to training has been reported to represent as high as 40% of the project’s sample. However, the incidence of poor responders to training can be ameliorated with manipulation of either the training frequency, intensity, type and duration. Additionally, global non-response to cardio-respiratory fitness training is eliminated when evaluating several health measures beyond just the target variables as at least one or more measure improves. More research is required to determine if altering resistance training variables results in a more favourable response in individuals with an initial poor response to resistance training. Moreover, we recommend abandoning the term “poor” responders, as ultimately the magnitude of change in cardiorespiratory fitness in response to endurance training is similar in “poor” and “high” responders if the training frequency is subsequently increased. Therefore, we propose “stubborn” responders as a more appropriate term. Future research should focus on developing viable physiological and lifestyle screening tests that identify likely stubborn responders to conventional exercise training guidelines before the individual engages with training. Exerkines, DNA damage, metabolomic responses in blood, saliva and breath, gene sequence, gene expression and epigenetics are candidate biomarkers that warrant investigation into their relationship with trainability. Crucially, viable biomarker screening tests should show good construct validity to distinguish between different exercise loads, and possess excellent sensitivity and reliability. Furthermore “red flag” tests of likely poor responders to training should be practical to assess in clinical settings and be affordable and non-invasive. Early identification of stubborn responders would enable optimization of training programs from the onset of training to maintain exercise motivation and optimize the impact on training adaptations and health.