It’s only a hypothesis, of course, and it matches my preconceived bias so naturally I hope it will eventually be proved.
Their argument: As humans transitioned from a relatively sedentary apelike existence to a more physically demanding hunter-gatherer lifestyle, starting around 2 million years ago, we began to engage in complex foraging tasks that were simultaneously physically and mentally demanding, and that may explain how physical activity and the brain came to be so connected.
The good news is that when you stop the intense exercise the effect dissipates. Not to get too personal here, but I have experienced this back in the days when I ran road races. I think the bottom line is that the body reacts to stress— any stress— and certainly intense exercise is a form of stress for the body.
A systematic review suggested that exercise intensity was a key regulator of gastric emptying rate, with higher intensity exercise (≥70% peak power output) causing the greatest disturbance to gastric motility, according to Ricardo J.S. Costa, MD, of Monash University in Victoria, Australia, and colleagues.
However, steady state moderate exercise (60-70% peak power output or 66% VO2max equivalent) did not appear to influence gastric emptying and intestinal transit compared with rest in well-trained individuals, they wrote online in Alimentary Pharmacology and Therapeutics.
This suggests that the body tries to heal, and exercise might help? It also suggests that a Ca score might not mean what everyone thinks it does. These are associations and correlations, it does not show or suggest causation. This is one of the papers discussed (abstract only).
The studies offer evidence that people who exercise for long periods and with great intensity appear to have an elevated risk for atherosclerosis. But, reassuringly, the atherosclerotic lesions that develop in intense exercisers are more likely to be characterized as stable.
Pooled data from 10 randomized controlled trials showed a significant 43% reduction in the risk of falls compared with other interventions at 12 months or less, and a reduction in the risk of injurious falls by 50% over the short term, Rafael Lomas-Vega, PhD, from the University of Jaén in Spain, and colleagues reported online in the Journal of the American Geriatrics Society.
The protective effect of tai chi diminished over time, such that the risk reduction dropped to 13% for falls and to 28% for injurious falls with follow-up of a year or greater, the researchers found.