The results were published in Neuropsychopharmacology.
Scientists believe exercise-induced endorphin release may in part be the body's way of motivating a person to power through activities that are no fun, but good for you. The new study, conducted at the University of Turku, shows that the popular (but miserable) high-intensity interval training leads to a burst of endorphin released into the brain, which the researchers speculate alleviates some of the physical and emotional stress caused by the awful, high-intensity exercise. A lower-tempo, less demanding, traditional and entirely reasonable one-hour aerobic routine, sadly, has no similar effect.
What Is HIIT?
HIIT is usually 30-60 minutes long. It switches between high intensity exercises to small active breaks. By making the body work hard, rest for a small amount of time, and then work hard again, it's able to grow stronger than just doing the same level of intensity for a prolonged period of time.
Since HIIT is so intense, most people who engage in it will only exercise three times a week. They enjoy this more because they don't feel as though they are always exercising. Instead, they achieve a phenomenal level of physical activity in a relatively short period of time. It really aligns well with how people live these days -- a "get it done" lifestyle.
People can engage in a HIIT by doing many different activities. Studies have found these intervals of exercise that push people to their limit can improve their:
- Cardiovascular system
- Respiratory health
- Metabolic functioning
- Other mechanical functions
It's possible that high-intensity interval training can help enhance quality of life and capacity to be health.
In the study, HIIT significantly increased the release of endorphins and other opioid peptides in the brain areas controlling pain and emotions. HIIT also induced negative feelings in the exercisers. Although one-hour aerobic exercise did not induce significant release of endorphins, it increased pleasurable feelings and euphoria. Said researcher Tiina Saanijoki: "Our results highlight that exercise intensity affects endorphin release and that the brain opioid system is involved in both positive and negative feelings caused by physical exercise performed at different intensities."
"Exercise-induced endorphin release may be an important mechanism which supports exercise motivation and maintenance of regular exercise. At moderate training intensities, the pleasurable sensations caused by the possible release of endorphins may promote habitual exercise. At very high exercise intensities the release of endorphins appears to be linked to increased negative feelings and pain, and may be needed to manage the emotionally and physically demanding challenge. However, such negative feelings may discourage further exercise."
Can It Slow Down Aging?
Well, it won't freeze you in time. More precisely, the team have found that HIIT helps to rejuvenate protein-building factories in our cells, known as ribosomes, and boosts the energy-producing capacity of our cells' powerhouses, known as mitochondria. As we get older, the ability of our mitochondria to generate energy dwindles. This study suggests HIIT can help to reverse the age-related changes seen in mitochondria.