There is nothing better than walking. Walking a mile everyday, or taking reasonable exercise three times a week, promises to reduce the risk of heart disease, as well as strengthens bones and keeps them strong.
The benefits of walking also includes: increased cardiovascular and pulmonary (heart and lung) fitness, improved management of conditions such as hypertension (high blood pressure), high cholesterol, joint and muscular pain or stiffness, and diabetes. Walking at least 30 minutes a day reduces the risk of heart disease and stroke by up to 27%.
I'll admit I didn't read hardly any of that study, but I caught the bit about the subjects already being on anti-depressants. I'd wager the effects of exercise on positive modd would be decreased on subjects who already have a chemical imbalance causing depression.
There could still be improvements in mood that wouldn't be severe enough to stop the use of antideperssants. Or maybe it's a perceptual thing, if you're already depressed, you may have a harder time perceiving an improved mood as significant enough to report.
My own experience tells me that exercise definitely improves mood. It's common sense that the endorphines released during exercise improve mood. Exercise also improves confidence and self-esteem.
The study also mentioned that subjects who started exercise were more likely to continue doing so after the trial period. Why is this? Mere habit? How does someone who is depressed find the willpower and perseverance to continue a workout regimine if it's not doing anything for their mood?
In any case, walking is better than nothing, it should maintain a baseline level of cv fitness, but you'll never run a marathon from walking. It all depends on what your goals are.
Walking is the simplest exercise and has the ability to reduce the risk of many health problems like obesity, diabetes, cholesterol and cardiovascular disease. It is also great to maintain body weight. Try to walk about 2 km in the morning and 1 km after having dinner, you will experiencing great results as the cardio exercises makes the heart strong and muscles get exercised through this.