A small improvement in isolation is just that, a small improvement, but if you add up all the small improvements it can be quite significant, even life changing. There is an incredibly long list of benefits from high intensity strength training. From the website Body By Science, some of less familiar more esoteric benefits of high intensity strength training:
-Reversal of age-related gene expression
-HIT/BBS enacts a hormonal cascade that is the antithesis of the metabolic syndrome.
-Gut motility correlates with muscle mass. Risk of GI cancer inversely correlates with gut motility.
-Organ mass correlates with muscle mass. Get in an accident or severely burn yourself and the time you have in the ICU before you die is correlated with organ mass. You have more time on the clock.
-Get in a car wreck and this kind of conditioning may be the difference between 3 days of whiplash symptoms and a lifetime in a wheelchair (which will be a shortened lifetime).
-Cardiovascular benefits (see JEP article by Steele et al).
-BDNF elevations with high intensity exercise staves off/reverses age related decline and dementia.
-Enhances nitric oxide synthetase: you will have good blood pressure and will never need a little blue pill. You will not need to worry about “being healthy enough for sexual activity”.
-Bone mineral density correlates with muscle mass. Even in osteopenia, strong muscles absorb forces and prevent fractures.
-Basal metabolism and hormonal profile that fight obesity.
There is an alternative to the positive changes produced by proper exercise. Do nothing; there will be a series of changes that will eventually result in a shorter compromised life.