Running with a 2kg dumbbell in each hand is a rare sight in Singapore.
Yet Dr Srinivas Subramaniam does that at least thrice a week - barefoot.
The kidney specialist covers around 10km each time, running around areas such as Holland Road, Pandan Valley, Ghim Moh, Commonwealth, Lornie Road and Bukit Timah.
"When you carry weights, your legs have to bear the additional load, so the leg muscles get strengthened," said the 46-year-old.
"At the same time, when I grip the weights, they work my biceps and forearm muscles, specifically the brachioradialis, which flexes the forearm at the elbow. So I get a two-in-one workout."
Dr Srinivas, who left Chennai for Singapore in 2009 for work, said he got the idea of running with weights by following Nordic walking, a Finnish total-body workout where people walk with specialised poles.
"The rationale for that is you burn more calories that way because you are also using your upper body strength," he said.
"So I was trying to figure out if we could adopt the concept of Nordic walking in running. And this is what I came up with."
Most professional runners don't run with weights for fear of risk of injuries but running with dumbbells can be good for conditioning for those who have good strength level.
It also makes the runner stronger, meaning it will improve speed and endurance, and strengthen the joints, reducing the risk of injuries.
"When you carry weights on your run, you are increasing the load your body has to move through space - which means you'll be pushing yourself a little harder," noted Dr Cedric Bryant, chief science officer for the American Council on Exercise.
"Working harder will increase your heart rate, which will lead to more calories burnt."
Walking or running with light weights strapped to the wrists or ankles is common, but not carrying 2kg dumbbells.
Principal physiotherapist Sai Ram Kumar of Synergy Physiotherapy and Sports in Singapore said: "Walking with weights is a common type of exercise, but running while carrying weights is not as common. This method of exercise is now being adopted by individuals based on their needs.
"While this type of activity can have potential physiological benefits, such as increased muscle strength, endurance and improved bone density, it may expose the individual to inadvertent muskoskeleteal issues unless adequate safety measures are integrated."
He cautioned that the extra weight can put an unwelcome strain on the muscles, joints and tendons, setting the stage for injury or chronic pain.
Dr Srinivas said he has been running for the past 20 years and has never suffered any injury.
"I usually do about 11km an hour but carrying weights slows me to 8km an hour," he added.
"But I love running because it improves my fitness. I also like to get out early in the morning, with the sun rising and the birds waking up. I see neighbours and smile and say hi to them. So there is a mental wellness benefit to it, too."
Dr Srinivas also explained he has no problem running barefoot "because I am very conscious of my surroundings".
"When you run barefoot, you are aware of where you are planting your foot and avoid stones, glass and metal pieces," he said.
"So it's actually safe. Runners get injuries because they wear shoes and do a 'heel strike', where the impact goes directly to the joints. Whereas when you run barefoot, you are more likely to land on your middle forefoot.
"There is a spring effect by the Achilles tendon and the calf muscles will function as shock absorbers. They protect your joints."
Dr Srinivas pointed out that the feet "have sensory organs that we tend to numb them by wearing footwear while running".
"By running barefoot, you get a free foot massage," he said.
"Anatomically speaking, there are as many nerve endings per sq mm in your foot as there are in your lips. So it's a very sensitive organ and activates circuits which provide health benefits."
Dr Srinivas, who is trim at 55kg, said running has made him strong and gives him plenty of energy to attend to his patients in his private clinic for up to nine hours a day.
"I have encouraged my wife, our two sons and everyone I meet to pick up running," he said.
"I may not ask everyone to run with weights, but I tell them to run because running is fun.
"It's enjoyable and makes you feel good. I start my day on a high."
"When you carry weights, your legs have to bear the additional load, so the leg muscles get strengthened. At the same time, when I grip the weights, they work my biceps and forearm muscles, specifically the brachioradialis, which flexes the forearm at the elbow. So I get a two-in-one workout."
- Dr Srinivas Subramaniam