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Jennifer Aniston's viral 15-15-15 workout builds 'strength and endurance' for over 50s

Nancy Best of Ladies Who Crunch breaks down Jen's workout

By Katy Daly, 29th March 2024

Since she shot to meteoric fame and success as Rachel Green in the hit sitcom Friends, Jennifer Aniston, and her lifestyle choices, have been the talk of the town. 

When it came to light that the actress, 55, had been eating Cobb salads on set everyone was out buying lettuce and a new chopping board to jump on the hype. But it is also the workout that sits alongside Jen's healthy diet that fascinates her fans. 

The Murder Mystery star admitted in an interview with InStyle that she follows what has been dubbed the 15-15-15 workout. What sounds like a complicated regime is actually super simple. 

The Marley & Me actress follows a plan that involves 15 minutes on a bike, followed by 15 minutes on a cross trainer, rounded off with 15 minutes on the treadmill.

"I had an injury last fall and I was only able to do Pilates, which I absolutely love," Jennifer recalled. "But I was missing that kind of sweat when you just go for it," she admitted, letting fans in on the 15-15-15 routine she picked up once recovered. 

"It's just old school," she said. "I can chase myself around a gym." But it isn't just a fun workout - using a cross trainer, in particular, is also greatly beneficial, especially for women over the age of 50, says personal trainer and founder of the online female fitness community, Ladies Who Crunch, Nancy Best. 

"Primarily, the cross trainer is a great form of aerobic exercise," Nancy tells us. "Building your cardiovascular fitness is an important element of overall heart health, as it improves your capacity to pump blood around your body."

As we age, using a cross trainer is lighter on joints while still feeling like you can get a sweat on. Nancy tells us: "Lower impact cardio is a hugely beneficial way to get your heart rate into a 'working' zone, without putting your body through too much stress.

"Using the cross trainer is a way to do steady state cardio. A continuing repetitive movement that works multiple muscle groups will give you all the mental health benefits of more intense conditioning, without risking impact injuries."

The personal trainer explains the risk of high-impact cardio in contrast to using a cross trainer. "While high-impact cardio is brilliant for boosting endorphins, it takes a toll on our joints and can restrict functional mobility," Nancy explains.

"After the age of 50, our bone density starts to decline, meaning our bodies lose bone faster than we can rebuild it. As you age, your chances of developing osteoporosis increase, making your bones fragile and more likely to break."

Nancy says this is particularly true of women going through the menopause. "Hormonal changes accelerate this process too; women can lose up to 20% of their bone density within five to seven years following menopause. Although the cross trainer alone will not build muscle mass, it does improve the strength and endurance of your muscles if you’re using a high resistance on the machine."

The benefit of a cross trainer is that it works your whole body to an extent, so it is great for those who don't have hours to spend in the gym devising a detailed and varied plan. "From your legs to your shoulders, to your core muscles, maintaining movement on the machine requires the recruitment of multiple major muscle groups," the fitness community founder tells us.

Fret not if you are not a gym-goer or do not have access to a cross trainer. Nancy reassures that a great alternative is brisk outdoor walking, with some kind of weighted vest, or weighted backpack, to mimic the resistance element of the machine.


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