Exercise as if your life depends upon it, it really does. Men who achieved >7 METs (highly to very highly fit) level demonstrated a 50%-70% lower mortality risk than “low fit” subjects.
In a study published in the Journal Circulation, researchers assessed “the association between exercise capacity and mortality” in over 14,000 men—subjects whose average age was 60, who did or didn’t have cardiovascular disease and who successfully completed a treadmill test. Men who achieved >7 METs (highly to very highly fit) level demonstrated a 50%-70% lower mortality risk than “low fit” subjects.
The highest-intensity aspect of exercise, the hardest part. is the 15 seconds of sprinting at the end of a long run, or the most difficult 10 seconds of pumping during a peak level on an exercise bike, or the last few repetitions when exercising muscles to failure. One “metabolic equivalent” [MET] is the amount of oxygen used by an average person at rest and increases proportionally with the intensity of exercise.
A MET is used as a practical means of expressing the intensity and energy expenditure of physical activities in a way comparable among persons of different weight; but actual energy expenditure (e.g., in calories or joules) during a physical activity depends on the person’s body mass, therefore the energy cost of the same physical activity will be different for persons of different weight. In other words, METs as defined by most exercise equipment cannot be used to determine metabolic rate directly. Never the less, a physical activity with a MET value of 2, such as walking at a slow pace (e.g., 3 km/h) would require for a specific person twice the energy that person consumes at rest (e.g., sitting quietly), a MET value of 1.
In this study, fitness categories based on METs achieved are were:
- low [5 METs]
- moderate [5-7 METs]
- highly [7.1 to 10METs]
- very highly fit [over 10 METs]
Subjects exercised until tired; with follow-ups done for 7.5 years on average. Men who achieved >7 METs (highly to very highly fit)—demonstrated a 50%-70% lower mortality risk than “low fit” subjects. The chances of staying alive increased by 12 to 13 percent with each increase of a single metabolic equivalent [MET] when exercising as hard as possible on a treadmill. Peak MET achieved is a better predictor of how long someone will live than other factors – including health risk factors like high cholesterol, diabetes, smoking, high blood pressure, and even heart disease.
The risk of death was reduced by 50% with an improved exercise capacity attained of just 30 minutes per session, 5-6 days per week. And even if 30 minutes was too much , splitting the routine into 10-15 minute segments (morning/evening) gives the same benefit. Additionally, even moderate intensity exercise, greater then 7 METs offers significant health benefits.
- Increased health span: A study following Harvard grads for 30 years showed those moderately active were at substantially decreased risk of death.
- Decreased health risks: Strengthening the heart muscle for good circulation, decreased blood pressure and reduced stroke risk.
- Reduced stress and significantly improved mood: With a moderate intensity workout of 20 minutes or more.
- Increased muscle endurance: Making daily activities easier.
- Improved sleep quality: Researchers at Stanford, Emory and the University of Oklahoma reported older people doing brisk walking and/or low-impact aerobics four times a week went to sleep faster and slept an hour longer than before (Harvard Health Letter, March 1997).
Many of these benefits accrue due to the improved endocrine profile; with resultant elevated Thyroid Hormone, Testosterone, and Growth Hormone. Insulin sensitivity also seems to be enhanced with improved glucose control, resulting in less fat deposition, increased fat mobilization as usable energy, and reduced total Insulin levels and elevated Glucagon levels.
The key element in obtaining health benefits is the high intensity nature of the exercise, and the relatively short duration of the exercise. MET capacity is even more important than the traditionally measured BMI or waist hip ratio.