Is It Safe to Do 4x4 Intervals When You’re Over 60?

Your heart’s ability to submit oxygen — your VO₂max — is the strongest known predictor of future health, independence, and longevity. And while VO₂max declines with inactivity and less with age, it is also highly trainable at any age.

That’s where the 4x4 method comes in.

Age Doesn’t Make You Less Able to Improve — Inactivity Does

Multiple studies over the last two decades have reached the same conclusion: older adults respond to high-intensity training just as well as younger adults.

A 2017 study by Støren et al. showed that adults across all age groups improved their VO₂max by 9–13% using interval training, with no drop-off in effect for people 60+.
Your training potential doesn’t disappear — it just needs the right stimulus.

High-Intensity Training Is One of the Most Effective Ways to Keep Your Heart Young

As we age, the heart and vasculature become stiffer, smaller, and less efficient. That’s the biological process behind reduced stamina, slower recovery, and higher disease risk.

A two-year study from the University of Texas Southwestern showed that including weekly 4x4 intervals in regular training could reverse decades of cardiac aging in middle-aged adults. Participants increased VO₂max by 25% and regained heart elasticity — a fundamental marker of youth.

If this is possible after decades of inactivity, maintaining heart function at 60, 70, or beyond is not only realistic — it’s protective.

So, is it appropriate to do 4x4 intervals 2–3 times per week at 60+?

Yes.
When performed correctly — 4x4 intervals are safe, time-efficient, and extraordinarily effective for older adults.

The Myworkout method is designed specifically around relative intensity:
You work at your body’s capacity, not someone else’s idea of “hard.”

At the right intensity, you should breathe markedly and not feel any other discomfort. A rule of thumb is that you should be able to continue for another minute at this intensity when the active break starts.

That means a 65-year-old might be walking uphill, not running — but still getting the full cardiovascular benefit.

Why This Matters So Much More After 60

VO₂max drops roughly 1% per year in the average population — faster with age and if you’re inactive.
Lower VO₂max strongly predicts:

• Higher cardiovascular risk
• Reduced physical independence
• Slower recovery from illness or surgery
• Lower overall resilience
  
  

The good news: Training can restore VO₂max far faster than it declines.

A 6–12% improvement — typical after 8–10 weeks of 4x4 training — can cut your biological risk profile by a decade or more.

A Real-World Example: Nolan Bushnell at 73

Tech legend Nolan Bushnell began training with Myworkout at 73.
His biological age dropped by three years in ten weeks — despite traveling, missing sessions, and not always hitting the target intensity.

His comment:
“Your stuff is working.”

Age didn’t block improvement.
Consistency unlocked it.

Bottom Line

Two to three weekly 4x4s are:

• Safe for healthy adults over 60
• Scientifically validated
• Highly effective at maintaining or improving VO₂max
• The fastest way to reduce biological age and long-term health risk
  
  

You are not too old for this. You are precisely the age where this matters most.