Record-breaking sailor Ellen MacArthur needs to be careful her body does not shut down following her 71-day voyage.
Ellen MacArthur would have put her body under incredible strain, experts say
The 28-year-old has been told to rest after becoming the fastest person to sail round the world single-handed.
During her voyage, she slept for only 20 minutes at a time, had to eat double her normal calories and haul sails twice her body weight.
Experts said her body would have been put under incredible strain, leaving her physically and mentally exhausted.
Professor Kevin Sykes, director of the Centre for Exercise and Nutrition Science at University College Chester, said the physical exertion would have meant she would have lost much of her muscle mass.
And he warned she could be close to exhaustion, which could ultimately lead to her body "closing down".
He told BBC News the risk would come once the adrenaline and endorphin wore off.
"It was an amazing physical and mental test. She must be very fit but there are still some risks.
"She must be careful she has a rest for a few days, maybe even weeks once all the TV and radio interviews are done."
However, Professor Sykes believes one advantage Ms MacArthur may have is her size.
At just 5ft 2ins the yachtswoman would not have had to eat too much to keep her energy levels up, he added.
"It would be different if it was a large man with lots of muscle, they could struggle to refuel."
Coping with the sleep deprivation may have been a little easier, according to Professor Jim Horne, head of Loughborough Sleep Research Centre.
"It is possible for the human body to get by only on 20 minutes' sleep for a while.
"Leonardo da Vinci did it when he was painting so the paint did not dry.
"I would not imagine she was sleeping for just 20 minutes for days and days on end, there would have been periods where she could have slept for longer periods.
"Sleeping just 20 minutes is long enough to give your body and mind time to recuperate.
"If you sleep for longer, you get in a deeper sleep which is harder to wake from."
Professor Horne said she now needed a couple of big "10-hour" sleeps for her body to return to normal.
Sports psychology consultant Vicki Aitken said the feat, completed on Monday night, would have required incredible mental strength.
"To achieve such heights requires a lot of concentration, but with sailing I would imagine there is also the temptation to start thinking about what you want to do when it's over.
"She now needs time to reflect on what she has achieved and what she wants to do in the sport in the future.
"You sometimes see athletes who win gold medals go flat the following year because they do not know what they want to do."