HIIT in Adolescence: A Barrier Against Cocaine Addiction
- Lidi Garcia
- Sep 23
- 4 min read
Chronic cocaine use causes brain changes linked to addiction. Researchers have shown that high-intensity interval training (HIIT) during adolescence reduced drug cravings in rats and increased levels of the ΔFosB protein, suggesting that exercise may protect against substance abuse.
In 2019, it was estimated that approximately 23 million people aged 12 and older suffered from substance use disorder. Among the most commonly used drugs, cocaine ranks second globally, behind only cannabis.
This drug acts on the brain by increasing levels of dopamine, a neurotransmitter associated with feelings of pleasure and reward. This occurs because cocaine blocks the reuptake of dopamine, preventing it from being removed from the space between neurons, intensifying its effects.
Repeated and chronic cocaine use causes structural changes in the brain, such as increased dendrite branching and an increase in the number of dendritic spines in regions linked to pleasure and behavioral control, such as the nucleus accumbens and prefrontal cortex. These changes reinforce drug-seeking.
Another associated factor is an increase in the ΔFosB protein, which accumulates after chronic cocaine exposure and is directly linked to addictive behaviors.
Several previous studies have shown that exercise can help both prevent and treat drug abuse. This is because physical activity also alters brain metabolism, including in the same regions activated by cocaine use.
In laboratory animals, exercise has been observed to decrease cocaine cravings, reduce relapses induced by external triggers (such as remembering the drug), and even block relapses caused by stress. In humans, exercise has been associated with decreased cravings and drug use.
Not all types of exercise have the same impact. High-intensity interval training (HIIT) has been shown to be more effective than moderate-intensity continuous exercise (MICT). Its benefits include greater improvement in cardiorespiratory fitness (VO2 max), reduced insulin resistance, blood glucose control, improved working memory, and increased adherence in sedentary individuals.
Previous studies have evaluated continuous exercise (HIIT) in adolescents and found that it decreased future cocaine cravings in females, but not in males. Until then, no study had tested the effects of HIIT on cocaine use at this stage of life.
In this study, researchers at the University at Buffalo, USA, investigated the impact of HIIT during adolescence on cocaine attraction in male Lewis rats.
The rats in the exercise group were placed on a treadmill for 30 minutes a day, completing ten three-minute cycles each, for six weeks. The treadmill speed was progressively increased until it reached 0.8 miles per hour (21.5 meters per minute).
After this period, the animals underwent a test called conditioned place preference (CPP), which assesses whether they spend more time in an environment associated with cocaine. The drug was administered at a dose of 25 milligrams per kilogram of body weight.
After the behavioral test, the rats' brains were analyzed to measure levels of the ΔFosB protein in the striatum, a region linked to motivation and habit control.
The results showed that rats that performed HIIT had:
19% less time spent in the cocaine-associated environment, indicating less attraction to the drug (B).
65% higher ΔFosB levels in the striatum compared to sedentary rats (A).
This suggests that HIIT exercise during adolescence has a protective effect against cocaine abuse, possibly through increased ΔFosB. Although this protein is known for its role in addiction, in this case it appears to be associated with an adaptation mechanism that helps reduce vulnerability to the drug.
These findings are relevant because they reinforce the idea that exercise, especially HIIT, can be an effective tool in the prevention and treatment of drug use. Because the study was conducted only on males, the researchers emphasize the importance of conducting further experiments with females as well and further investigating the biological mechanisms that explain this effect.
READ MORE:
High Intensity Interval Training (HIIT) exercise in adolescent rats results in cocaine place aversion and ΔFosB induction
Nikki Hammond, Nabeel Rahman, Sam Zhan, Mark S. Gold, Kenneth Blum,
Teresa Quattrin, Yun Young Yim, Eric J. Nestler, and Panayotis K. Thanos
PLoS One. 20(9): e0316228.
Abstract:
High-Intensity Interval Training (HIIT) is a form of exercise that has been greatly popularized over the past few years for its many health benefits. Similar to other forms of exercise, HIIT may be beneficial in the prevention of substance use behaviors; however, the extent to which HIIT can impact the reinforcing effects of drugs of abuse during adolescence has not been fully evaluated. Here, we assess the effects of HIIT during adolescence on subsequent cocaine conditioned place preference (CPP) in male Lewis rats. The HIIT exercise exposed rats ran on a treadmill for 30 minutes daily (ten three-minute cycles) for six weeks with progressive speed-increased up to 0.8 mph (21.5m/min), while the sedentary rats remained in their home cage. Following the six weeks of exercise, rats were tested for cocaine (25 mg/kg) CPP. Following completion of the behavior test ∆FosB levels were measured in the brain. Results showed that the HIIT rats showed significantly attenuated place preference (−19%) in their time spent in the cocaine-paired chamber compared to the sedentary environment rats. In addition, HIIT rats had significantly higher (65%) striatum ∆FosB levels compared to the sedentary rats. Our findings show that HIIT exercise during adolescence could be protective against cocaine abuse which may be mediated by an increase in ∆FosB. This finding has important clinical implications with respect to exercise mediated protection against substance misuse and abuse. Future studies will examine this effect in females as well as the potential underlying mechanisms.
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