Track cyclist Azizulhasni Awang and other top athletes are being monitored by the World Anti-Doping Agency (WADA) as they prepare for the Tokyo Olympics.
Random, out-of-competition anti-doping tests have become the norm for them as WADA look to stamp out cheating in sport.
In general, the more successful an athlete is, the more he or she will be tested.
And it is no different for Azizulhasni. The Olympic bronze medallist and former world keirin champion is often subject to random tests wherever he may be, at any time of day.
The 33-year-old is used to receiving unexpected visits from anti-doping officials looking to collect both urine and blood samples.
"WADA include elite athletes in their Registered Testing Pool (database) and these athletes need to (constantly) update their latest whereabouts. WADA have the right to make surprise visits anytime," said Azizulhasni.
"Throughout my professional career, I have always given my cooperation and I have been tested hundreds of times.
"I have experienced visits (from officials) very early in the morning and also very late at night, even while on holiday when you least expect them.
"There were also times when I was out of the house and received a phone call from an unknown number which turned out to be from an (anti-doping official) who is already waiting outside your house.
"The testing process can take one or two hours and I cannot go anywhere until the procedure is completed.
"Recently I had just returned from tarawih prayers and was about to prepare a meal for my daughter when the doorbell rang.
"It turned out to be a 'special' visitor (anti-doping official).
"They already came around last month but decided to drop by again (to conduct test). The process lasted about two hours."
While doping cases in track cycling have been relatively rare, the use of performance-enhancing drugs has been a major issue in road cycling over the last few decades.
On a positive note, stricter, frequent testing appears to have made it tougher for cheats to get away over the past few years.
Azizulhasni, who won Malaysia's first Olympic medal in cycling in 2016, hopes to deliver the nation's first ever Olympic gold in Tokyo.