Exercise gets harder the less you do, here is why.

New research suggests that a vital protein in the body may be deactivated if one reduces their exercise routine, leading to more inactivity and making it harder to exercise.

Scientists from the University of Leeds have made a new finding that deactivating the Piezo1 protein, which acts as a blood flow sensor, can lead to a decrease in the number of capillaries that transport blood to the muscles.

The team discovered that restricted blood flow makes physical activity more challenging and can result in decreased exercise capacity. These findings shed light on the biological reasons behind the difficulty of exercising when one is not active enough.

The paper titled “Endothelial Piezo1 Sustains Muscle Capillary Density and Contributes to Physical Activity” has been published in The Journal of Clinical Investigation.

The experiments were carried out in mice, but the Piezo1 protein is found in humans, suggesting the same results could occur.

Fiona Bartoli, the lead author and a Postdoctoral Researcher at the University of Leeds’ School of Medicine, explains that exercise offers protection against a range of diseases, including cardiovascular disease, diabetes, depression, and cancer. However, many individuals do not exercise enough due to reasons such as injury or excessive computer usage, which increases their risk of these diseases. Furthermore, individuals who exercise less become less fit, which often leads to a negative cycle.

While there are numerous known responses to exercise, the initial molecular trigger for the benefits of exercise remains a mystery. Our study emphasizes the critical connection between physical activity and physical performance, which is established at the molecular level by Piezo1. Maintaining the activity of our Piezo1s through exercise may play a vital role in our overall physical performance and health.

In the experiment, two sets of mice were compared by scientists – a control group and another group whose Piezo1 levels were disrupted for 10 weeks. The mice were observed while walking, climbing and running on a wheel, and it was observed that the Piezo1 mice had significantly lower levels of physical activity. This indicates that Piezo1 plays an important role in maintaining normal physical activity.

The researchers conducted a study to investigate if Piezo1 mice showed less interest in exercise. However, they did not find any differences in the amount or duration of activity between the two groups. Instead, they observed that the Piezo1 mice had fewer running wheel revolutions per exercise session and a slower running speed, indicating a reduced ability to exercise rather than a lack of desire.

Professor David Beech, the lead author in the School of Medicine at the University of Leeds, has revealed new insights into the connection between Piezo1’s role in blood vessels and physical activity. While its involvement in blood vessel development was already established, its contribution to vessel maintenance in adults was less understood.

This new discovery presents a chance to explore alternative methods of treating muscle loss. By activating Piezo1, there may be a possibility of preserving one’s ability to exercise. The study was financially supported by the British Heart Foundation.

Journal Reference:

1. Fiona Bartoli, Marjolaine Debant, Eulashini Chuntharpursat-Bon, Elizabeth L. Evans, Katie E. Musialowski, Gregory Parsonage, Lara C. Morley, T. Simon Futers, Piruthivi Sukumar, T. Scott Bowen, Mark T. Kearney, Laeticia Lichtenstein, Lee D. Roberts, David J. Beech. Endothelial Piezo1 sustains muscle capillary density and contributes to physical activity. Journal of Clinical Investigation, 2022; 132 (5) DOI: 10.1172/JCI141775

The article originally appeared in: 

University of Leeds. “Why exercise gets harder the less you do.” ScienceDaily. ScienceDaily, 28 February 2022. www.sciencedaily.com/releases/2022/02/220228191000.htm.