Gardening is an activity well known for promoting peace of mind. In fact, there's even something called "horticultural therapy", where gardening is used to help people recover from emotional and mental difficulties.
However, the benefits of gardening go beyond the purely psychological. Regular spells of outdoor work will bring you the same advantages as any other kind of physical activity - including a reduced risk of cardiovascular disease. And you can tailor your gardening routine to suit the demands of your health regime.
For example, you can build up your strength and stamina by engaging in more strenuous gardening activities like lawnmowing or raking, while the regular stretching involved in things like digging and weeding should improve your overall flexibility. You can increase the effectiveness of these exercises by regularly changing your position, and exaggerating your movements (for instance, digging with big, broad and sweeping actions).
Try thinking about your time in the garden as an applied fitness session - mix up your chores so you do a number of different types of activity in each gardening session, and you'll be giving yourself a proper workout.
Of course, as with any period of exercise, it is important not to put yourself under too much strain. Make sure you're physically warmed up before you start to prevent muscle strains, and drink enough water to replace any lost bodily fluids during your gardening time. Also, don't forget to lift any heavy weights carefully - bend your knees and let your legs take the strain rather than your back.
Remember, gardening should be about enjoyable exercise, rather than becoming a gruelling endurance test. There's no reason to push yourself beyond what you can comfortably achieve. And the best thing about getting fitter through regular gardening is that you should soon see really impressive results - not just in yourself, but in the flowerbeds too.