A recent five-year randomized study suggests that the intensity of physical activity has little impact on mortality risk, but that being active is better for quality of life.
The benefits of physical activity are immeasurable. It’s little wonder that it is one of the most important public health measures for maintaining good health. It helps to; improve body composition, reduce chronic diseases, Foster adoption of other healthy habits, and reduce the risk of death. All these interactions lead to the consensus that physical activity is the cornerstone of good health at any age.
The British Medical Journal recently published a randomized study conducted over a five year period by Norwegian and Australian researchers. The study aimed to answer the question of whether intensity also plays a role in increasing life expectancy besides the frequency of sport in older adults.
The Norwegian city of Trondheim was selected to be the study site. Subjects aged between 70-77 were recruited by applying the following exclusion criteria:
- Uncontrolled high blood pressure (untreated systolic blood pressure > 220 mm Hg or diastolic blood pressure > 110 mm Hg)
- Symptomatic valve disease
- Hypertrophic cardiomyopathy
- Unstable angina pectoris
- Primary pulmonary hypertension
- Heart failure
- Severe cardiac arrhythmias
- Diagnosed dementia
Finally, 1,567 people participated in the study. Subjects were randomly divided into three groups:
- The HIIT (High-Intensity Interval Training) group was commissioned to have two 10-minute activity sessions per week.
- The Moderate Intensity Continuous Training (MICT) group was assigned two sessions of 50-minute per week.
- The control group followed the national public health guidelines for physical activity (i.e., 30 minutes of activity per day).
Monitoring was done every six weeks. Key data including exercise compliance were collected at year one, three, and five. The researchers first wanted to know how these different types of training programs influence the mortality rate. Secondly, they decided to record and measure changes in cardiorespiratory health and self-reported quality of life. They considered these two factors as important indicators for predicting longevity.
A Slight Effect on Longevity
The study showed that the effect on mortality between the groups is not significant, suggesting that intensity is not a decisive factor for longevity. However, significant improvements in the respiratory condition were noted among HIIT and MICT groups compared to the control groups. Similarly, the HIIT group reported improved quality of life at the end of the study.
First, participants in the control group had a higher frequency of physical activity throughout the study and often performed their tasks by doing HIIT-type exercises. It is possible that this makes some of the differences between groups to be insignificant. In addition, more than half of the people in the HIIT group were unable to follow the program requirements strictly and rigorously. There is also a suspicion of bias in the selection, as the recruited participants were all much healthier than those excluded from the protocol.
Finally, the authors suggest that future physical activity guidelines, at least for older adults, should be more specific by requiring that at least part of the exercise be performed with high intensity.