On Monday, Ms Evelyn Lee, 77, goes for a pulsating kickboxing session at The Star Vista in Buona Vista.
On Tuesday, the retiree heads to either Lot One Shoppers' Mall in Choa Chu Kang or IMM Building in Jurong for KpopX fitness, aerobics incorporating K-pop moves.
And on Friday, the fitness enthusiast, who lives in Choa Chu Kang, busts out more K-pop moves at JCube in Jurong or Junction 8 in Bishan.
And these exercise classes do not cost her a cent.
She says: "I don't need a gym membership and seldom attend classes at the community club. I can exercise at the mall for free."
Yes, these days, it is possible to get workouts at the malls every day of the week.
Since 2010, the Health Promotion Board has been working with shopping centres to organise exercise sessions.
These activities, aimed at making exercise more accessible to the masses, are led by professional instructors.
Most are paid for by the board or the malls, but they declined to reveal cost figures.
At least 12 malls, mostly in the heartland, now offer such activities regularly, and more than 13,000 people have participated in them.
The sessions, which are mostly an hour long, include mall walks and aerobic activities such as zumba, kickboxing and KpopX fitness.
For example, a KpopX fitness session at Lot One on the first and last Tuesday of the month typically consists of 14 songs - a warm-up song, 12 songs for an intense workout and a cool-down song.
Says freelance instructor Suzanne Kuo, 25, who was engaged by interior design and events company Cityneon: "These exercises can benefit one's health, such as improve energy levels and mental alertness and reduce the risk of chronic diseases."
There are also yoga sessions, such as the ones held on Thursday at The Star Vista, organised by the mall in collaboration with yoga studio Meraki Yoga.
At the studio itself, a similar session could cost $17 to $43.
Says yoga instructor Jacqueline Soon, 29: "When doing yoga, it's important for each participant to focus internally.
"There might be music playing from the shops or people staring at you. But if you focus on your breathing and poses, it's easy to block out all the surrounding noise."
Yoga participant Jolin Liu, 23, a student, agrees: "It's sometimes easy to get distracted when doing yoga in a mall. But I remind myself to concentrate.
"After all, it's just for one hour and I can do what I want afterwards."
Those who prefer less rigorous exercises can go for mall walks, during which an instructor leads participants to walk briskly around a mall before the shops open for business.
These typically start with 10 minutes of stretching, a 1km walk around the mall, and then 10 minutes of cool down.
Says instructor Stephanie Tan, 26, who conducts mall walks: "The exercise is of moderate intensity. It should increase your heart rate and make you breathe deeply. You should still be able to talk, but not sing."
The Health Promotion Board recommends that adults and seniors engage in at least 150 minutes of moderate intensity aerobic activity each week, such as brisk walking, jogging, cycling and swimming.
Indeed, part-time library assistant Tan Thor Kee, 58, lost 2kg in two months when she started going for the walks three years ago.
"After the walks, I sleep better, feel more energetic and don't feel as tired when climbing stairs," she says.
"I've participated in other walking activities in the park or around my neighbourhood. But whenever it rains, everyone will dash for shelter. This doesn't happen during mall walks as they are conducted in a sheltered area."
As malls are usually near MRT stations, they are easily accessible to many of the participants.
Says IT officer Wendy Goh, 37, who attends about four exercise sessions every week: "After work, before each session, I'll change into my sports shoes and outfit in the mall toilet.
"After the session, I'll go home in my workout attire. It doesn't feel uncomfortable since the mall and trains are air-conditioned."
The activities have been well received by participants and attendance has been very encouraging, notes Dr Shyamala Thilagaratnam, director of the Health Promotion Board's preventive health programmes and regional and community health divisions.
Since the activities were introduced in 2010, the number of participants has increased by 40 per cent each month on average.
At some venues, up to 60 people - including working adults, seniors and youth - show up regularly.
Dr Thilagaratnam notes that people were attracted to the malls' facilities and their locations near homes and offices.
The Health Promotion Board says it is looking to partner more malls in the future.
Of all the participating malls, The Star Vista seems to organise the most number of regular exercise sessions - four a week - including kickboxing, yoga, zumba as well as a zumba and gym session for parents and kids.
These take place at its open-air Star Plaza, which has a 33m-high ceiling.
Ms Sherry Lee, 29, whose workplace is just one MRT station away, attends zumba sessions there every Tuesday evening.
After the sessions, it takes her just 30 minutes to get home, which is three MRT stations away.
Says the health-care worker: "It's more convenient than going to a big gym in town.
"Working out in a big group is more fun than in a small class. When you are surrounded by people, the atmosphere is very lively and you can really feel the adrenaline.
"Before you know it, one hour has breezed by."
About 90 per cent of the participants are women. But that is not stopping men such as Mr Tan Jun Ren, 24, from joining the free exercise sessions.
The student, who lives along Holland Road, has been attending kickboxing and zumba sessions at The Star Vista for the last three months.
"Many of my male friends don't want to come because they think that the exercises such as yoga and zumba are for women," he says.
"But the sessions are good exercise, free and just a 15-minute walk from my flat. It'd be silly of me not to go."
"I may be 77 years old, but I can still do zumba and kickboxing. I love to stay active. The only session I won't go for is yoga, because my body is not flexible anymore."
RETIREE EVELYN LEE, who attends classes at malls about three times a week
"I love that the exercises take place on the mall's premises. Before the session, I can window-shop with my friends. After the session, I buy groceries at the supermarket."
HOUSEWIFE RUBY ABDUL KADIR, 48, who has been going for KpopX fitness classes for the last month
"I don't care if strangers stare at me. Korean singer Psy's Gangnam Style and Gentleman are so catchy. I just focus on the steps and let the music carry me away."
BEAUTICIAN PEGGY TAN, 46, who attends zumba and KpopX fitness sessions at malls regularly