Many health impacts of aging are due to inactivity—not getting old
This past winter I taught a course titled "Physical Activity and Aging." It was a fun course, and really drove home an issue that I've known for a while, but hadn't previously given a lot of thought: the impact of aging is identical to the detraining that happens in response to reduced physical activity and/or increased sedentary behaviour.
Aging is associated with reduced fitness, weaker bones, reduced insulin sensitivity, reduced muscle strength, and reduced balance. Lack of physical activity is also associated with all of those things. This isn't a coincidence – many (probably most) of the health impacts of aging are not really due to aging at all.
You see, there are 2 types of aging. Eugeric aging, which you can think of as "true" aging. The stuff you simply cannot avoid as you get older (e.g. hearing loss, or reduced eyesight).
But there is also "pathogeric" aging, which refers to pathological aging (e.g. aging that's unecessary/unhealthy). Almost all the really scary things that we attribute to aging (weak bones, bones, heart, lungs, etc) falls into this category, and are much more likely to be caused by too little exercise/too much sitting, rather than aging itself.
I bring this up because I'm concerned that we are currently killing our elders with kindness. We don't let them carry their dishes to the sink ("Mom, sit down! I can get that!"). We won't let them do chores. We worry if they have to go up and down stairs on a daily basis. We get angry if they go for a walk without a chaperone. We force them to sit to conserve their energy. All of this flies in the face of evidence, and common sense. Picture the healthiest older adult that you know – do they spend their day sitting down, or do they spend their days walking, skiing, or dancing? It's not a coincidence.
If I were to take a healthy 20 year-old, force them to sit all day, and refused to let them do any physical labour out of fear they might hurt themselves, I would cause them to "age" extremely rapidly. We call it detraining, and we've known about it for decades. Put a healthy young person in a bed for less than a week and their metabolic health goes to hell – blood pressure increases, as does the amount of fat in the blood, while insulin sensitivity plummets by over 65% (details here). And yet that's the life that we often push upon the elderly out of fear that they might hurt/tire themselves out of they engage in too much physical activity (fun fact – exercise helps you sleep better, which is a good thing at all ages!).
What's worse, there is often a vicious cycle – a person does less activity as they age, which causes reduced fitness. That reduced fitness makes it harder to be active, so their activity levels drop more. Which means fitness drops more. And then muscle strength starts to slip. Which means even less activity, further reductions in fitness, and difficulties doing activities of daily living, or even living independently. You get my point. The good news? Even modest amounts of exercise result in increased functional and aerobic fitness, as well as improved metabolic health (details here).
We need to promote more, not less physical activity for our elders. We should cheer them on when they decide to do physical chores, and encourage them to do more. The next time to consider telling your grandmother to sit down, think about whether that's really in her best interest.