Thanks for joining me for another edition of the SerenityThroughSweat blog. I was listening to the Huberman lab podcast and was introduced by guest Dr. Peter Attia to a concept called “backcasting” which I wanted to share with you.
Dr Peter Attia is a physician who specializes in extending his patients’ life span and health span. He went to medical school at Stanford and worked at both John’s Hopkins and the NIH. He recently authored the book Outlive and also hosts his own podcast The Drive on health and medicine. He is a pretty highly qualified guy in the space.
During the conversation with Huberman (another very informative voice in the space of health and wellness) he introduced the concept of backcasting with the following question. What do you want the last decade of your life to look like?
This is called the Marginal decade. “Delineate the objective function and break that down into metrics that we can measure” you can set the goal posts for what you want your marginal decade to look like, and work backwards to find definable goals and measurable markers and at what ages you need to hit them
What do you want to be doing in your marginal decade? Picking up a grandchild, getting up off the floor, have an athletic hobby. Living alone. Do you want to be paddle boarding, bicycling, still driving your car?
If I ask you what is going to happen next year you can predict certain variables and make some educated guesses. This would be a forecast. The period of time is fixed and defined. You don’t know when the last decade of your life will be. Even if you did, there are likely too many variables to forecast that far out. But you can backcast.
Start with the desired outcome and trace the markers you need to hit in order to reach it. Let’s say for example you want to be able to go for a brisk walk on the beach every morning in retirement in your 80’s or even 90’s. That sounds like a nice goal and not outlandish.
“The gravity of aging is more vicious than people realize and therefore the height of your glider needs to be much higher than you think it is when you are our age if you want to be able to do the things we probably want to be able to do when we’re ninety “
Studies show that VO2Max (your ability to process oxygen during aerobic activity) declines roughly 5% per decade after 30, almost regardless of exercise intervention. As Dr Attia so eloquently put it. You need a lot of altitude for that glider flight into your marginal decade.
A VO2Max of 35-45 is considered fair to good for males in their 30s. This can be tested very scientifically in a lab while wearing a mask on a treadmill, but many running watches or fitness wearables can give a pretty good estimation for general purposes.
From there the math isn’t hard to cary out if you are right in the middle of average at a VO2Max of 40 in your 30’s, by the time you are 80 it will be closer to 30.
Murtagh et al., 2002 (4), investigated self-selected speed of recreational walkers and their interpretation of “brisk walking”.
It turned out that the self-selected speed, which was between 1.55 and 1.6 meters per second, resulted in an exercise intensity of almost 60% of VO2max and a heart rate of 67% of the maximum. A “brisk” walking speed observed was 1.79 meters per second in a parc and 1.86 meters per second on a treadmill. The “brisk” walking speed equated to almost 69% of VO2max and 78.5% of the maximum heart rate.
By your 80’s in our example your VO2Max has dropped a full 25% (and that’s likely best case if you remained healthy and active for those 5 decades). And that brisk walk you wanted to take (4mph is the conversion) was already taking up 69% of your VO2Max. That means you are going to have to slow your pace considerably or reduce the duration of you walk to meet your goal.
Or as Dr Attia told us, increase the height of your glider now in middle age. If your VO2Max is closer to 50 or 60 in your thirties, that brisk walk (all other variables constant) in your 80’s is much more attainable.
The same benchmarks can be set for strength in individual muscle groups or specific movements. Squats, pushups, pullups, grip strength. Gravity is unrelenting, as is the “vicious gravity of aging”. The Stronger you are now and the more you continue to train, the higher you can climb the glider, and the longer you can stay aloft.
Backcasting gives you the tools to set yourself up for success, once you have defined what you want your marginal decade to look like.
So stretch out those glider wings and keep climbing. gravity is thus far undefeated, but that doesn’t mean you can’t prolong, and thoroughly enjoy the ride.
Thanks for joining me,. stay safe and stay sweaty my friends.