Climbing to hills is one of the things most of the people want to do, but it is really hard. The treks give first-timers exposure to trekking without a high risk of Acute Mountain Sickness, or AMS.
The trips range from four days for treks in the region to 22 days for climbs up to the peaks. But those who are used to living 15m above sea level, these hikes can be a challenge. According to Singapore Sports Medicine, AMS usually affects travelers above 2,700m, but can start as low as 2,400m.
Symptoms of AMS are rarely life-threatening. They include headaches, shortness of breath while performing ordinary activities, loss of appetite, nausea, hallucinations, insomnia and general malaise. In rare instances, it can require a helicopter evacuation.
According to Dr Tian, travellers should "avoid intense exertion for the first 24 to 48 hours after arriving at altitude and consider taking acetazolamide, also known as Diamox - a prescription drug which speeds up acclimatization and reduces the severity of symptoms".
Ms Pauline Tan, 49, Ace Adventure Expeditions co-founder, says the best way to avoid AMS is to acclimatise at the destination before starting on the trek.
She adds: "When the starting point for the trek is already at a point of high altitude such as in Leh, which at 3,500m is the starting point for treks in Ladakh, India, I recommend arriving two or three days in advance to give the body time to adjust to the lower oxygen levels."
Another trick is to "climb high and sleep low", she says, a method which entails climbing up to a point with a higher altitude and staying there for a short while before descending and sleeping at a lower altitude.
"It is a good technique to expose the body to higher altitudes for a short period of time," she adds.
For avid trekkers such as Ms Olive Poh, 34, who has been on three high-altitude treks in Nepal, India and Taiwan, training prior to the trip is key.
"AMS can hit even the fittest of trekkers, so instead of worrying about what might happen, I focus more on training to walk 8 to 10km a day, so that I am not overwhelmed on my trek," the dance instructor says.
"Besides ramping up my cardio, I also do a lot of strength training for two months before the trip to make sure my muscles do not get fatigued easily."
The best way to train for a high- altitude trek? Climb the stairs in high-rise buildings with a backpack and gradually increase the weight in your bag. This will enable you to carry the roughly 5kg daypack on your expedition, used to hold necessary items such as water and outerwear.
The 30-year-old Shoma, who works in finance, recalls being hit by intense headaches and insomnia on the third day of the trek, at a height of 3,600m. By the fifth day, she was vomiting multiple times. Her oxygen levels fell to 50 per cent, at which point her guide made the call to evacuate her.
"I wasn't expecting AMS as I had done some high-altitude treks in the past and never experienced it," she says, recalling feeling incredibly weak and disoriented.
"That's the thing about AMS - it is very unpredictable and can hit anyone regardless of fitness level."
As for Mr Ang, whose army boots fell apart during his descend from Everest Base Camp, it was sheer luck that got him through to the end.
"I ended up wearing sports shoes for the tail end of the trek, which was dangerous because they didn't have much grip or traction," he says. "My advice is to invest in good-quality equipment for your trip. Ultimately, that will keep you safe through your trek."
Still, despite the scare that Ms Low went through, she says she is open to possibly going on another high-altitude trek.
"It was a scary experience and I might just be more prone to AMS than other people, but there is still something that draws me to trekking," she says. "I might just attempt it again in the future."