Should you lift light weights or heavy ones? At 79, Arnold Schwarzenegger has a simple answer: both. In his latest Pump Club newsletter, the former Mr. Olympia explains why mixing the two keeps muscles strong, and why heavier sets matter even more as we get older.
In short
- In his Arnold’s Pump Club newsletter of November 10, 2026, Schwarzenegger explains that light and heavy weights can both build muscle.
- The key, he says, is to take your sets close to failure.
- He recommends lifting heavier, relative to your own strength, at least once or twice a week, because fast-twitch muscle fibers tend to shrink first with age.
Light or heavy? Both work
According to Fitness Volt, which reported on the newsletter, Schwarzenegger’s main point is reassuring: you don’t need to lift huge weights to build muscle. “Light weights grow slow-twitch just fine, but heavy lifting does too,” he writes.
What matters is effort. Whether the load is light or heavy, the sets need to be taken close to failure, the point where you can barely complete another repetition with good form.
Why heavy sets matter more after 60
Here is the part that speaks to anyone over 50. “Fast-twitch fibers tend to shrink first as we get older,” Schwarzenegger notes. These are the fibers that produce power and speed, the ones we rely on to climb stairs quickly, catch ourselves when we trip or get up from a low chair.
Heavier loads may favor those fibers. “Heavy sets may get there sooner and keep those fibers working longer,” he explains. That is why he suggests pushing a heavier weight, relative to your own strength, at least once or twice a week.
What the science says
Schwarzenegger points to a recent analysis of people who had thigh-muscle biopsies before and after about 10 weeks of heavy or light training. “The fibers grew about the same regardless of load,” he summarizes, while noting that the fiber-type trials were small and that the researchers called the results exploratory.
This echoes a well-known 2017 meta-analysis led by Brad Schoenfeld in the Journal of Strength and Conditioning Research, which found that low-load and high-load training produced similar muscle growth, while heavier loads led to greater gains in maximal strength.
How to apply it
- Keep most of your sessions at a weight you can control well, and take the last reps close to failure.
- Once or twice a week, choose a heavier weight for a key exercise, relative to your own level.
- “Heavy” is personal: what matters is the effort, not the number on the dumbbell.
- If you’re new to strength training or have joint issues, start light and ask a professional for guidance.
Stars who keep training for life
Schwarzenegger joins a list of stars who credit simple, consistent habits for their strength, like Helen Mirren and her 12-minute routine or Mick Jagger and his training mix.
At 79, the man who made bodybuilding famous still has the same message: keep lifting, light or heavy, and keep going.
