width=160A new study of almost 4,400 Americans has found that staying moderately fit and active may help you live longer.

The study was of healthy adults, also taking into account other health factors such as obesity and diabetes. The researchers found that the 20% with the lowest fitness levels were twice as likely to die within the next nine years, as the 20% with the next-lowest fitness levels.

Research took place between 1986 and 2006, assessing fitness levels with a treadmill test, and following participants for an average of nine years. The study was published in Medicine & Science in Sports & Exercise.

Only 6% of the fittest men and women died during the follow-up period, compared with 25% of the least fit.

The researchers found even those participants whose exercise didn't match up to the minimum recommended levels were still less likely to die.

So, don't feel if you can't make five 30-minute sessions a week that it's not worth exercising. The message here is that even a modest increase in your fitness level can have a significant effect on your lifespan.

And, it's never too late to start. The participants in the study had reported similar levels of activity throughout their lives, but it was their most recent level of fitness which mattered most.

If you're a senior unsure about taking up exercising, you might find Old Dan's Story (on Diet Blog Share) inspiring.