Physiologia, Volume 4, Issue 3 (September 2024) – 2 articles

Background: Menopause is a significant period in the life of a female; many hormonal and lifestyle changes occur, which can have a catastrophic effect on their health and well-being. Amongst these changes is the loss of muscle mass and strength. Resistance training is recommended for post-menopausal women; however, the role of protein in muscle mass and strength in this population is unclear. Methods: This narrative review discusses the research evidence regarding daily protein needs, dose and timings of intake, and protein quality. Results: Observational and interventional studies suggest post-menopausal females should ingest at least the RDA 0.8 g·kg⁻¹·d⁻¹ of protein, the dosing at each meal maybe important. Both whey and soy protein may provide some benefit to muscle strength. Conclusions: Overall, there is limited evidence and not of high quality, making it difficult to make inferences about the protein needs of post-menopausal females. Full article

Researchers have hypothesized that high-intensity interval exercise (HIIE) and moderate-intensity continuous exercise (MOD) lead to different patterns of shear stress in the brachial artery. These differing patterns of shear stress are thought to partially explain the differing chronic adaptations to these two types of exercise. No study has directly compared blood flow characteristics during HIIE and MOD. Sixteen healthy males (Age: 23 ± 3 years) completed two randomly assigned exercise visits: HIIE (10 × 1 min intervals at 90–95% of HR_max with 1 min of recovery between) or MOD (30 min at 70% of HR_max) on an electronically braked cycle ergometer. Brachial artery blood flow velocity and diameter were measured for a total of 12 min during each of the exercise sessions. Both anterograde blood flow (MOD: 191.3 ± 80.3 mL/min, HIIE: 153.9 ± 67.5 mL/min, p = 0.03) and shear rate (MOD: 203.5 ± 78.1 s⁻¹, HIIE: 170.8 ± 55.5 s⁻¹, p = 0.04) were higher during MOD compared to HIIE. Both retrograde blood flow (MOD: −48.7 ± 21.3 mL/min, HIIE: −63.9 ± 23.3 cm/s, p < 0.01) and shear rate (MOD: −51.5 ± 19.8 s⁻¹, HIIE: −73.8 ± 28.4 s⁻¹, p < 0.01) were of greater magnitude during HIIE compared to MOD. During exercise, brachial artery diameter (p = 0.34) did not differ between HIIE and MOD. Continuous moderate cycling exercise leads to higher brachial artery anterograde shear rate and blood flow, but lower retrograde shear rate and blood flow when compared to high-intensity interval exercise. These differences during exercise in blood flow characteristics could shed light on the differing chronic adaptations to these two types of exercise. Full article