Fitness starts slipping in your mid-30s, new study finds

Technology Dec 22, 2025

A Swedish study tracking people from their teens into their 60s found that strength and endurance actually peak around age 35—then start to drop off.
So, the idea that you only lose fitness much later? Not quite true.

What else did they find?

The decline happens for everyone, but women may see muscle power dip a bit earlier than men.
By your early 60s, fitness can drop by up to 48% from its peak.
The good news: even if you pick up exercise later in life, you can still boost your fitness by 5-10%.
Basically, staying active at any age really does pay off.