Age-related changes can occur in your body in your late 20s and 30s, but for many people, it’s the big 4-0 birthday that really hits home the idea of “aging.”

Let’s first be clear that aging is more of a mindset than something that’s set in stone. And, your lifestyle can be instrumental in slowing down (or speeding up) the hands of time.

Toward that end, exercise is about as close as you can get to a real-world fountain of youth. The right types of exercise can prevent age-related muscle loss, stave off cognitive decline and even trigger mitochondrial biogenesis, a decline of which is common in aging.

This reverses significant age-associated declines in mitochondrial mass, and in effect stops aging in its tracks.¹

How to Optimize Your Fitness After 40

The first step is to simply get moving, but beyond that you’ll want to tweak your workouts for your 40-year-old self. This does not mean taking it easy — it means tailoring your workouts so you can be in the best shape of your life, even if you’re 40 or beyond.

Work on Flexibility

Research published in the American Journal of Physiology found that an inability to touch your toes while in a seated position (sitting on the floor with your legs stretched out in front of you) might mean your arteries have become stiff, and you have an increased risk of heart attack or stroke.²

The study found participants’ flexibility scores correlated with their blood pressure, cardio-respiratory fitness, and other measures of heart health. Plus, losing flexibility — which happens as you get older if you don’t do anything to stop it — increases your risk of injuries and makes it harder to stay active.

Yoga and foam rolling can be useful for increasing flexibility, and I also recommend active isolated stretches developed by Aaron Mattes.

With Active Isolated Stretching, you hold each stretch for only 2 seconds, which works with your body’s natural physiological makeup to improve circulation and increase the elasticity of muscle joints.

This technique also allows your body to repair itself and prepare for daily activity. You can also use devices like the Power Plate to help you stretch and increase flexibility.