I’m back with another piece of interesting research which was recently published. Interesting not because of its conclusion, which is apparently obvious to those who have lived a physically cultured life. But interesting because of the size of the study and the age of the study population. A group in Brazil recently published an absolutely massive study that asked the simple question: How does power influence death? More specifically, they were interested in the relationship that a simple endurance metric (handgrip dynamometry) has with all-cause mortality. And they did it in 1980, adults, men and women, over 90 years old. And about five years after the handle test, they went back to see what the survivor rates looked like.

This type of research is considered a prospective cohort study, meaning that the researchers measured a group of people (in this case, grip strength) and looked at an outcome (all-cause mortality) that they were going to follow him in a certain time. period (~5 years). When conducting this type of research, the outcome measure is what is called a “hazard ratio.” This can be considered the probability of something happening. In the case of this study, where the outcome measure was all-cause mortality, a hazard ratio of 1 would mean that there is no association of grip strength with death. Anything greater than 1 is more likely to result, anything less than 1 is less likely to result. And it’s all based on percentages, with the difference from 1 being the more or less likely percentage. For example, a hazard ratio of 1.3 is 30% more likely, while a hazard ratio of 0.7 is 30% less likely to result in the outcome. There, now you know the epidemiology.

So what did they find? For starters, they found the average grip strength for men to be 26 kg (~57 lbs) and for women to be 16 kg (~35 lbs). What kind of context does this fit into? Well, it’s hard to say. There are no real standards for people that old. But looking through some of my exercise physiology textbooks, I found that the normal range for ages 70-99 is 21.3-35.1 kg for men and 14.7-24.5 kg for women. So we could say they were probably average given that they were at the higher end of that age range. As for the associations they found, the researchers noted that those in the 90th percentile (that is, 10% of strength) had a 25% lower chance of dying (hazard ratio 0.75 ). And, perhaps more tellingly, those in the 10th percentile (bottom 10% of strength) were 27% more likely to die (33% for men!). And the conclusion of the data distribution was that there is no power threshold. For every bit stronger you can stay, you’re less likely to give up.

Now, one problem with these types of studies is that they have to sacrifice some level of control because there are so many subjects. The researchers controlled for things like BMI, smoking status, and other variables that could be measured. But they couldn’t control for things like genetic predispositions, access to quality health care, or other dietary or physical activity factors that occurred in the 5 years between the test and follow-up. But given that these individuals were all over 90 years of age, we might assume that some degree of robust and healthy life was present. And even if the actual percentages are off a bit due to confounding variables, the clear trend of endurance benefiting longevity is there.

The most important takeaway here is that the best day to start strength training was 20 years ago. If you missed it, then the next best day is today. There are a lot of factors that play into health and longevity, and being strong is definitely one of them.