Almost one in five women and one in 10 men are feeling "extremely stressed" as they start the year, new research suggests.
Experts have warned that stress pushes up blood pressure, putting people at higher risk of stroke.
A poor diet and lack of exercise also contribute to the chances of suffering a stroke.
According to the poll of 2,000 people, almost a fifth said they "take no exercise whatsoever". A similar number said they manage only 30 minutes of exercise once a week.
More than a quarter of middle-aged people (45 to 54) said they never exercise, despite suffering the highest stress levels.
James Beeby, of the Stroke Association in the UK, said: "The research is incredibly worrying and emphasises the need for the public to be aware of the dangers of stroke."