Your Limits When Exercising Can Be Mental
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Recent research has unveiled specific neurons in mice that enhance endurance following exercise, suggesting that similar cells may exist in humans. These findings could pave the way for targeted drugs and treatments to amplify exercise effects.
Traditionally, the understanding has been that brain changes from physical activity differ from those occurring in muscles. However, Nicholas Betley from the University of Pennsylvania contends that these brain changes regulate all physical responses.
To investigate further, Betley and his team observed neuronal activity in mice before, during, and after treadmill sessions, concentrating on neurons located in the ventromedial hypothalamus. Previous research revealed that developmental issues in this area hinder fitness improvements, a finding likely applicable to humans due to the structural consistency across mammals.
Post-exercise, the researchers noted that a specific group of neurons with SF1 receptors exhibited increased activity. These neurons, critical for brain development and metabolism, activated more significantly with each subsequent run. By day 8, approximately 53% of neurons were activated compared to under 32% on day 1. As Betley emphasizes, “Just as your muscles get stronger through exercise, your brain’s activity adapts as well.”
Utilizing optogenetics, which uses light to manipulate neuron activity, the researchers turned off these neurons in another mouse cohort trained on the treadmill five days weekly for three weeks. Observed post-session, neuron inhibition lasted an hour, followed by endurance tests.
The findings showed that these inhibited mice improved their running distances by around 400 meters, compared to control mice whose neuron activity remained unaffected.
While the exact function of these neurons remains ambiguous, team member Morgan Kindel, also at the University of Pennsylvania, indicates their likely role in fuel utilization. During endurance exercises, carbohydrates are depleted faster, necessitating a shift to fat for fuel. However, when these neurons were inhibited, mice utilized carbohydrates earlier, leading to performance limitations. They also discovered that inhibiting these neurons hindered the release of a muscle protein, PGC-1 alpha, which optimizes fuel use, while also facilitating energy replenishment and muscle recovery.
Although optogenetics isn’t applicable to humans due to its invasive nature, Betley suggests potential alternative interventions could be developed to target these neurons. “If we can identify methods, like supplements, to activate these neurons, we could significantly boost endurance,” he states.
In experiments boosting neuron activity instead of suppressing it, the mice exhibited extraordinary endurance, able to run over twice the distance of control subjects.
Such advancements may particularly benefit individuals struggling with exercise, including the elderly or stroke survivors, as noted by Betley.
Nevertheless, several challenges remain. First, the applicability of these findings to humans is not confirmed. There are concerns about potential side effects, highlighted by Thomas Barris at the University of Florida. These neurons seem to regulate cellular energy uptake, and overstimulation might pose risks like dangerously low blood sugar levels.
Even if safely activatable in humans, Betley believes it won’t serve as a stand-alone solution for health. “Exercise fosters a wide array of benefits: reducing depression and anxiety, enhancing cognitive function, improving cardiovascular health, and strengthening muscles,” he notes. However, stimulating these neurons alone won’t unlock all the positive outcomes associated with exercise.
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Source: www.newscientist.com
