Exercise can boost mood - but it must be the right pace for your age
Exercising vigorously only boosts happiness if you are aged between 40 and 59 years of age, according to new research involving 28 countries, including Ireland.
And it found that the more days per week people aged 18 to 49 exercise moderately, the happier they are.
The same moderate exercise prescription applies to the over-70s who want to improve their mental wellness, said lead author Bernd Frick, professor of sports economics in the University of Paderborn in Germany.
The findings challenge the "one-size-fits-all" guidelines from the World Health Organisation (WHO), which said we should clock up 150 minutes of moderate or 75 minutes of vigorous exercise a week.
Previous research has found that physical activity significantly adds to subjective wellbeing among all age groups.
However, the effect of the intensity of physical activity has not been investigated.
It still remains unclear how exercise affects mood or boosts serotonin levels. The research now suggests separate exercise recommendations for different age groups.
"The findings suggest that the 'happiness' impact of exercise intensity differs considerably between the age groups," said Prof Frick.
Moderate exercise generates fewer mental good feelings for men than for women.
And yet women who exercise vigorously get less benefit overall from the intense activity than men. The happiness was measured using the person's own subjective wellbeing.
"What I would like to add with respect to Ireland is that Irish people are already very happy," Prof Frick told the Irish Independent.
"They are among the most happy people in Europe, although they exercise far less than people in other countries. "Thus, if our results are robust - and we have every reason to assume they are - Irish people could even be happier if they exercised at least at the level at which the rest of us in Europe do," said Prof Frick, who recently discussed his study at the ESRI in Dublin.
Moderate exercise involves very brisk walking, washing windows, mowing the lawn, cycling at 10kmh to 12kmh or playing tennis doubles.
Vigorous exercise includes hiking, jogging at six miles an hour, carrying heavy loads, fast biking, playing soccer or singles tennis.
"My findings challenge the physical activity recommendations issued by various national and international health organisations," said Prof Frick.