Being at sea for months, racing boats around the world, can lead to a raft of issues that may cause a whole heap of stress.
Sleep deprivation, lack of exercise and diet, and missing home are some of the triggers.
But exactly how stressful conditions may negatively affect the body is only now being looked into, in a study of members of Team Alvimedica in this year's Volvo Ocean Race.
The research - The Stress of Sailing: Volvo Ocean Race Study 2014-15 - is being done by medical experts and academics from universities in the US, Britain and Sweden.
Each of the team's eight-man crew undergoes various tests before and after each leg of the race.
Dr Stefan Branth, of Uppsala University and Dr Martin Ugander, of Karolinska Institute in Stockholm, are on the research team.
Dr Branth said the intense conditions provided a unique opportunity to measure stress.
"Stress is one of the major killers in the world ... So this research is important to try and understand the effects of long-term stress. In the end, we will know a lot more about how the body reacts to stress. This is good for the crew itself as we can give them individual advice on what they need to [change] - what to eat, exercise and so on."
In Auckland last week, the sailors underwent several tests looking at the activity of the heart, analysing blood and looking at body composition.
Within the crew - made up of men from the US, Italy, France, New Zealand and Australia - are Aucklanders Dave Swete and Ryan Houston.
Houston, 31, said some days were particularly hard when they could get only a few hours sleep.
"The aim is to get at least six to eight hours, but it's hard. Then because we're on such a small space, we don't get to run or walk as much and we lose muscle in our legs."
Swete, a former pupil of the then Rutherford High School, said it was more of a mental game than anything else.
"For me, it's been mentally stressful because the race has been so close; but also when we've gone to places where there hasn't been a lot of wind and that's stressful."
Leaving his daughter Ella, 2, and the rest of his family was also a burden at times. "Leaving the dock - when you hear all the music and the crowds and trying to say goodbye to your family, that's hard.
"Then when you get further out, it gets all quiet and you look around and see everyone else and it's just back to the job. Your mind changes back."
Team physio Paul Wilson is also a Kiwi and has previously worked with Team New Zealand and the Auckland Blues.