Fighting Frailty with High Intensity Interval Training (HIIT)

The aging process is often associated with physical frailty. However, a preclinical study recently performed at the University at Buffalo shows this does not have to be the case. The study determined short periods of intense physical exercise can be performed at advanced ages to combat or even reverse frailty. The results of this study were recently brought to light in the Journal of Gerontology. It is the first study to investigate if short but intense exercise sessions, known as high intensity interval training, referred to with the acronym of " HIIT", could provide benefits to older populations.

This research project was funded by private foundations along with the Indian Trail Charitable Foundation and the United States Department of Veterans Affairs. Bruce R. Troen MD served as the study's senior author. Kenneth L. Seldeen, Ph.D., served as the study's first author.

About the Study

The study involved two groups of mice. Each group consisted of a dozen two-year-old mice. This age equates to an age of 65 in human years. Each mouse involved in the study lived a sedentary life until this age. The purpose of the study was to determine if HIIT might help reduce frailty during the aging process. Frailty puts people at a heightened risk for death and comorbidity. Comorbidity is the simultaneous presence of multiple chronic diseases in a patient. 

The study's lead researchers created mouse equivalents to measure human frailty. Examples include evaluations of gait speed, endurance and grip strength. They established baseline level and compared them with the results following the study's completion. The program of exercise is applicable to people as the performance measures for rodents have relevancy in terms of clinical parameters. Though mice are fairly identical in terms of genetics, they are not identical in terms of phenotype. So each mouse's exercise program was fully customized.

The study involved a 10-minute program of physical activity with a warm-up period of three minutes. Intervals of exercise performed at varying intensities were performed three times per week across 16 weeks. The mice tolerated the exercises quite well.

The Results

The researchers found five of the six mice that were pre-frail or frail showed improvement. Four of the mice were no longer frail at the study's end. These four mice showed deficits that correlate to human frailty improved to quite the robust level. The study's results show HIIT boosts quality of life and one's capacity to enjoy a healthy existence. The research team found mice showed significant improvements in an array of measurements ranging from general physical performance to strength.

HIIT completely reversed frailty in four mice. The mice enjoyed significant grip strength improvements, faster gait speed, and improved treadmill endurance. They also enjoyed greater muscle mass and a boost in mitochondria. Mitochondria are cells' energy factories. An increase in mitochondrial biomass allows for a more efficient use of oxygen. HIIT boosted muscle mass as well as fiber size and mitochondrial biomass.

Why is HIIT so Beneficial?

The researchers believe HIIT provides such significant benefits due to the stress it applies to the body. Exercise stresses the body, promoting beneficial responses. These benefits are especially meaningful if the exercise is intense in nature. The body responds quite well to HIIT's short but robust and vigorous exercise periods. However, those who are considering this method of exercise should not jump right into extremely intense physical activity. Readers are advised to consult with their physician prior to engaging in intense physical activity of any sort.