Around three in 10 teenage boys admit they have cried because they are stressed out by exams, according to a poll.
It also suggests around half of young people have felt so anxious before sitting a paper that they thought they could not do it - with girls more likely to feel this way than boys.
The survey of 1,000 16 to 17-year-olds, published by the National Citizen Service (NCS), found 51% of those questioned said they had cried due to exam stress.
A gender breakdown shows 29% of young men admitted they had felt this way, along with 73% of girls.
In addition, around 48% of the teenagers polled agreed they felt so anxious before an exam that they thought they would be sick (34% of boys and 61% of girls).
And 51% said they have felt so anxious before an exam that they thought they could not do it - with 39% of boys agreeing with this, compared with 63% of girls.
The NCS said it was working with mindfulness expert Danny Penman to give teenagers and their parents practical help on easing stress during exam season.
Youngsters across the UK are now taking exams for GCSEs and other qualifications.
Dr Penman said: "I discovered mindfulness when I was a stressed-out student. What I discovered is that mindfulness can help you cope when life seems overwhelming, whether you're a teen sitting exams or a parent who is deeply concerned about your son or daughter.
"The simple steps we're sharing at www.ncsyes.co.uk can easily be incorporated into daily life and can help break the cycle of anxiety, stress, unhappiness and exhaustion at exam time or when results are looming."
:: The ICM poll questioned 1,000 16 and 17-year-olds at the start of the year.