“Women didn’t work out,” she said. “(They) weren’t meant to have muscles, and they weren’t meant to sweat, and I kind of changed that.”

Fonda, who will be 83 in December, is as toned and flexible as she was nearly four decades ago. This April, the fitness icon made her TikTok debut, reviving her signature leg lifts on the social media platform and inviting her followers to work out with her to help bring attention to the climate change crisis.

Common aerobics exercises that burn calories and increase flexibility include step touches, knee lifts, leg raises, jumping jacks, box steps, a dance move called the “grapevine”, and kicks. These are usually performed in a sequence with a short break between exercises.

According to Joan Liew, a Singapore-based fitness trainer and co-founder of the Fitness Factory, aerobics is beneficial and convenient in so many ways.

“It improves your overall fitness, endurance and stamina, depending on the type of exercises you do, their intensity and how frequently you do them. Plus, it relieves stress, engages your mind, and requires you to focus on getting the exercises right,” Liew says.

“Unlike many other workouts, aerobics can be done at home, even if you have a small space. And you don’t need much apart from comfortable clothing, an exercise mat and perhaps a pair of dumbbells and resistance bands.”

After six months, they were found to have performed better on certain thinking and memory tests. The researchers believed that this was due to increased blood flow to regions of the brain that specifically improve verbal skills, memory and mental sharpness.

“At a time when these results would be expected to be decreasing due to normal ageing, to have these types of increases is exciting,” said study author Marc Poulin.

Fonda doesn’t just exercise to keep physically fit; it also makes her feel good and keeps depression at bay, according to an interview she did with The Washington Post in 1990, soon after the release of her workout video, Jane Fonda’s Light Aerobics and Stress-Reduction Program.

But it’s not only the upbeat music and colourful leotards that will put a smile on your face when you do aerobics – countless studies over the years have shown that cardiovascular exercise stimulates the production of the mood-enhancing chemicals like serotonin, dopamine and norepinephrine.

Aerobics is generally safe, but Liew warns that the wrong technique and form may cause injuries. “That’s the main danger with following online workouts – there’s no trainer with you to observe your technique and correct it if needed.”

If you are not in good physical condition, have been sedentary for a long time or have never exercised before, Liew does not recommend you kick off an exercise regime with aerobics. You should also avoid the activity if you have a serious underlying medical condition, such as heart disease, or if you’ve just had major surgery. Instead, she suggests getting advice from a doctor or fitness professional first.

Fonda was famous for catchphrases like “feel the burn” and “no pain, no gain”, and while it’s normal to be slightly breathless and to experience a little tightness in your muscles while working out, it’s important to remember not to go overboard.

“To get the most out of your session, go for 30 minutes of high intensity or 45 minutes of moderate intensity, and aim for an elevated heart rate and body temperature,” Liew advises. “And, don’t forget to stretch. Pre-workout, your stretches should be light and dynamic. Post-session, they should be deep and static to help keep your body supple and flexible.”