If you ask Charles Eugster, 96, "retirement" is a dirty word.
A bodybuilder and sprinter who has set multiple world records in his age group in races ranging from 60 meters to 400 meters, Eugster is basically the fittest 96-year-old on the planet. While nutrition and exercise are certainly integral in his tips for healthy living for the aging population, there is one other factor above all.
"Retirement is one of the worst things that you can do to yourself,'' Eugster told TODAY from his home in Zurich, Switzerland.
"If you refer to the queen of England, who just turned 90, she has a terrific schedule. She is not somebody who jogs in the park of Buckingham Palace, but she does an enormous amount of standing. She is not someone who sits, and sitting is not healthy. The most important thing is that she has a job."
Eugster, who was born in London in 1919 and has dual British-Swiss citizenship, was a dentist for much of his adult life after earning degrees from four different universities. A twice-married father of two, he then produced a dental newsletter from when he was 75 until he was 82. Single since the death of his second wife in a car accident 14 years ago, one of his goals for when he turns 97 in July is to write a book.
More Health Tips videos
1-minute meditations to calm your mind
Watch KLG and Regis learn yoga moves to help them sleep better
How to unplug your life
Do toilet seat covers really protect you from germs? Experts say…
"We must do everything in our power to see that older people are healthy and productive because if we don't do that we are facing enormous problems between pension liabilities and our health costs,'' he said. "We should have retraining facilities for older people. You are throwing away the skills and expertise of people at 65, and that is absolutely ridiculous.
"After retirement age, depression doubles every five years. I personally think that has a lot to do with retirement. It's an enormous strain if you're not making a contribution to society."
Eugster also stresses that you're never too old to get in shape. He didn't start doing any serious weight training until he was 87, and he didn't start running until he turned 95.
He began working out three days a week in a gym with a former Mr. Universe to put on muscle and also lost 24 pounds before he turned 88. Eugster is currently working with a trainer to get his "beach body" ready for summer despite a hamstring pull at a race on April 13.
"At 87 I began to notice that in spite of rowing six days a week that my body was deteriorating, and being an extremely vain person I didn't like the way that I looked and I needed more muscle,'' he said. "I think being vain for an older person is an asset.
"By the time you get to 85 you may have lost about 50 percent of your muscle mass and power, so I think it's extremely important in your older age to do everything you can to build muscle."
More Diet and Fitness videos
How fitness, fellowship and faith are bringing thousands of men together
3 yoga poses to wake up your body
Man loses 374 pounds in 3 years
Eat this, not that: Try these small swaps to save big calories
Eugster offered TODAY some exercise and diet tips for those looking to jump-start their fitness later in life.
- Employ high-intensity interval training: "It takes less time to do and can be good for your heart."
- Train less if you have an aggressive regimen: "I was rowing six days a week, but now I only train three days a week because you need to have a day of recovery, which is when the muscles are built."
- Trim that waist: "In old age, you have to be far more careful of having a fat belly. It's the visceral fat that engulfs your organs, and that is the fat that is extremely dangerous especially in old age because it causes inflammation. It's one of the first stages of chronic disease."
- Try something new: "Learning a completely new sport is something extremely beneficial for your body and your mind. You have to develop new synapses in your mind in order to do completely new movements under pressure."
- Use protein supplements: "If you want to build muscle in old age, you have to take protein supplements, usually in the form of whey protein and leucine. A Vitamin D supplement is also very important because deficiency is very common in older people."
- Maintain a diet with variety. "I don't think it's a right idea to have a fixed diet where you're eating the same thing. You should eat all sorts of different things. An interesting thing I have now discovered is that if you consume a lot of protein, it's advisable that you start consuming fat, which is something that is a bit difficult to do because everything in the grocery store is low-fat or no-fat now."
Eugster's hope is to change the way the aging population is valued while also helping anyone getting up there in years know that life can be even better as you get older.
"In my opinion, you can rebuild your body at any age,'' he said. "You can learn something new or start a new life at any age."
Follow TODAY.com writer Scott Stump on Twitter.