Newswise — Rockville, Md. (April 11, 2019)—New research suggests that exercising early in the day protects brain blood flow from some of the negative effects from hours of sitting. The first-of-its-kind study is published ahead of print in the Journal of Applied Physiology. The paper was chosen as an APSselect article for April.

Previous research has established that prolonged sitting can reduce blood flow throughout the body, including to the brain. Protecting the brain against declines in brain blood flow is important to maintain brain health in aging adults. An international team of researchers studied a group of overweight adults between the ages of 55 and 80 to measure the combined effects of exercise and sedentary behavior session on brain blood flow.

The volunteers participated in three different trials separated by at least six days. The order in which each participant completed each trial was random. The trials were:

  • The volunteers sat uninterrupted for eight hours.
  • The volunteers sat for one hour, walked on a treadmill at medium intensity for 30 minutes and then sat for 6.5 hours.
  • The volunteers sat for one hour, walked at medium intensity for 30 minutes and sat for 6.5 hours, but also completed three-minute, light-intensity walks every 30 minutes.

The research team measured blood pressure, heart rate and blood flow to the middle cerebral artery (MCA) before the participants ate breakfast (before they sat for the initial hour) and other times during long sitting periods. The MCA is one of the main arteries that supplies blood to the largest and uppermost section of the brain (cerebrum).

In all trials, blood flow in the MCA was highest at the beginning of the day. Throughout the morning until lunchtime, blood flow dropped by about 20 percent when the volunteers sat continuously, and it stayed at that reduced rate for the rest of the day. But in both exercise trials, blood flow increased again in the afternoon instead of remaining lower. When the volunteers took frequent exercise breaks, blood flow increased earlier in the day than when they exercised for 30 minutes and then sat for the rest of the day.

“Our results show that the majority of the benefit, in terms of brain blood flow, is coming from the morning bout of exercise. If people can fit in a morning bout of exercise before sitting for the rest of the day, they will be protected to a degree from the effects of prolonged sitting,” wrote Michael Wheeler of The University of Western Australia, and first author of the study.

Read the full article, “Morning exercise mitigates the impact of prolonged sitting on cerebral blood flow in older adults” published ahead of print in the Journal of Applied Physiology. It is highlighted as one of this month’s “best of the best” as part of the American Physiological Society’s APSselect program. Read all of this month’s selected research articles.

NOTE TO JOURNALISTS: To schedule an interview with a member of the research team, please contact the APS Communications Office or 301-634-7314. Find more research highlights in the APS Press Room.

Physiology is the study of how molecules, cells, tissues and organs function in health and disease. Established in 1887, the American Physiological Society (APS) was the first U.S. society in the biomedical sciences field. The Society represents more than 10,000 members and publishes 15 peer-reviewed journals with a worldwide readership.