How different types of exercise impact mood and brain chemistry

Aerobic routines and mind-body practices like yoga both relieve anxiety and lift momentary moods, but getting the heart pumping is necessary to trigger the release of certain biological molecules. These results, published in the journal Psychoneuroendocrinology, show that while diverse workout routines offer psychological benefits, the underlying internal processes vary by activity.

Physical activity sets off a cascade of physiological responses throughout the human body. Among these reactions is the release of exerkines, which are signaling molecules secreted into the bloodstream by tissues during exertion. Researchers study these molecules to understand exactly how working out improves mental health and cognitive function.

Two major categories of exerkines are endocannabinoids and a protein called brain-derived neurotrophic factor, often abbreviated as BDNF. Endocannabinoids, primarily molecules known as AEA and 2-AG, bind to the same nervous system receptors as the active compounds in cannabis. These naturally produced chemicals help regulate pain, mood, and stress responses.

The BDNF protein supports the survival of existing neurons and encourages the growth of new connections in the brain. Mental health professionals frequently seek to harness these biological mechanisms to assist with treatments. Therapists use interventions like exposure therapy to help patients overcome severe anxiety, a process that requires the brain to form new, safe memories. Scientists are investigating whether a quick bout of exercise immediately after a therapy session can flood the brain with exerkines and cement those memories.

These internal chemicals are often credited for the euphoric feeling commonly known as a runner’s high. In people with psychiatric conditions such as post-traumatic stress disorder and major depressive disorder, the baseline levels of these molecules are frequently altered. These individuals also tend to show smaller biological responses to behavioral interventions, suggesting that altered chemical signaling plays a role in psychological distress. Restoring this balance through movement offers a promising pathway for psychiatric care.

Past research has established that sweating through a moderate aerobic workout can reliably elevate levels of circulating exerkines. Less is known about whether alternative, lower-impact activities provide similar physiological boosts. Some clinical populations face physical or motivational barriers that prevent them from engaging in traditional cardiovascular workouts. This makes accessible options like yoga highly appealing for psychiatric treatment plans.

A team of investigators sought to address this gap by directly comparing the psychological and biological impacts of specific exercise modalities. John Leri, a researcher at the Dell Medical School at The University of Texas at Austin, led the project alongside colleagues from both the Texas institution and The University of Alabama. They wanted to measure state affect, which refers to a person’s immediate emotional experience, alongside changing levels of circulating exerkines.

The study involved 88 young adult participants who were randomly assigned to one of two experimental groups. One group participated in aerobic exercises, while the other group took part in mind-body routines. Participants in the aerobic group completed two separate 30-minute sessions on a stationary bicycle, returning to the laboratory after a one-week delay.

During one cycling session, subjects pedaled with moderate resistance to maintain their heart rates at roughly 70 to 75 percent of their maximum capacity. For their other session, participants pedaled slowly without resistance, keeping their heart rates below half of their maximum.

The mind-body group followed a parallel schedule, completing two distinct half-hour routines guided by pre-recorded videos. One session featured a low-intensity, posture-based yoga practice that included mindfulness cues, breath awareness, and a final relaxation period. The alternative routine consisted entirely of basic stretching exercises without any meditation instructions.

Before and immediately after the exercises, the research team asked subjects to rate their momentary anxiety levels and their positive and negative emotional states. Medical staff also measured the participants’ blood pressure and drew blood through venipuncture. Lab technicians later analyzed these blood samples to detect exact concentrations of AEA, 2-AG, and BDNF.

Collecting the blood at distinct intervals allowed the team to capture the immediate biological aftermath of the activity. Venipuncture took place in a designated phlebotomy room within the laboratory, minimizing any external stress that might skew the results. The samples were then processed in a centrifuge and frozen at extremely low temperatures before being shipped to a specialized laboratory in Germany for rigorous analysis. This biological tracking provides a deeper look into the body than psychological surveys alone.

The protocol also featured a specialized cognitive challenge to test learning and memory. Before hitting the exercise bike or the yoga mat, participants viewed images on a computer screen and learned to associate specific visual contexts with the likelihood of receiving a mild physical shock.

After finishing their workout and providing a second blood sample, participants completed a follow-up assessment. They had to recognize the previous contexts without the explicit labels and recall which images were novel or familiar. Researchers included this phase to see if the chemical changes brought on by physical activity would enhance memory consolidation.

When analyzing the blood samples, Leri and his team found that only the moderate-intensity cycling session distinctly altered endocannabinoid levels. The concentration of AEA in the bloodstream rose after the continuous, heart-pumping workout. Neither low-intensity cycling, yoga, nor stretching produced measurable changes in AEA.

The scientists did not observe changes in the other endocannabinoid, 2-AG, across any of the experimental conditions. Even the moderate aerobic session failed to increase this specific molecule. Levels of the BDNF protein were similarly unaffected by all four routines, contradicting previous studies that noted immediate BDNF spikes following moderately strenuous workouts.

While the biological signals varied, the psychological rewards were much more universal. All four activities effectively decreased feelings of negative emotion and state anxiety across the board. Simply moving the body for a half hour, regardless of the format or intensity, helped participants shed tension.

Positive emotions displayed a slightly different pattern. The moderate cycling, the yoga flow, and the stretching routine all increased participants’ positive emotional states. In contrast, the low-intensity cycling group did not yield statistically significant improvements in positive affect.

The data also revealed a link between the shifting exerkine molecules and mood. Among the participants who experienced the largest increases in circulating AEA, researchers recorded parallel boosts in positive emotional states. Neither the endocannabinoids nor the BDNF levels showed any relationship to how well participants performed on the memory test.

The research team had anticipated that individuals with the highest exerkine levels would demonstrate superior memory retention during the contextual threat assessment. However, the data revealed no relationship between the internal biological markers and cognitive performance. The researchers suspect that the short time window between the initial learning and the follow-up test might have hindered their ability to detect actual memory consolidation effects. True consolidation processes often take place over days rather than hours.

The authors noted a few underlying factors that might explain some of the unexpected biological outcomes. The lack of a BDNF response during the moderate aerobic sessions could relate to the specific duration of the workout. The protocol required 20 minutes of continuous moderate exertion, which might be too brief to launch the metabolic triggers required to release the protein.

Additionally, the designated yoga routine was intentionally designed to be gentle and accessible for people of all fitness levels. Traditional yoga encompasses a vast spectrum of practices, and vigorous sequences might produce entirely different physiological demands. The current findings specifically reflect a low-impact session rather than an exhausting, sweat-inducing flow.

Leri and his colleagues suggest that future studies should test more strenuous yoga routines to see if they can match the cardiovascular strain of moderate cycling. Expanding the pool of research subjects to include older adults and individuals with specific psychiatric conditions would also help scientists tailor exercise recommendations. Different populations may require distinct movement prescriptions to maximize the mental health benefits of physical activity.

The study, “Contributions of yoga and aerobic exercise to acute changes in state affect, circulating BDNF and eCB concentrations, and memory,” was authored by John Leri, Kevin M. Crombie, Luna Malloy, Lily Wang, Paige Broski, and Josh M. Cisler.