You may have heard this expression lately, "sitting is the new smoking."

The costs for excessive sitting: the increased risk of serious diseases and the infliction of pain throughout the spine. The reason we get shorter as we get older is due to the loss of moisture also known as turgor in the discs of the spine. This causes the vertebrae to get closer together allowing for the facets of the vertebrae to ride up into the nerve roots causing back pain and sciatica pain.

Modern fitness research offers many potent reminders that physical activity is one of the best "preventive drugs" for many common ailments, from psychiatric disorders to heart disease, diabetes and cancer.

Many studies have also confirmed that prolonged sitting is an independent risk factor for disease and early death. So it's no major surprise to find that inactivity may be costing the global economy tens of billions of dollars each year in lost productivity and healthcare costs.

As reported by Reuters and others, a recent study looking at data from 1 million individuals worldwide found that lack of physical activity had a global price tag of $67.5 billion in 2013.According to their findings, however, one hour of daily exercise could eliminate a majority of these expenses. Inactivity is also the cause of more than 5 million deaths per year. To put that into perspective in terms of being a risk factor, smoking kills about 6 million annually. The World Health Organization (WHO) recommends getting a minimum of 150 minutes of moderate exercise each week, but even this may not be enough.

Ulf Ekelund, Ph.D., a senior fitness scientist and professor at the Norwegian School of Sports Sciences and Cambridge University, told Reuters:

"You don't need to do sport or go to the gym ... but you do need to do at least one hour a day," he said, "giving walking at 5.6 km [3.5 miles] an hour (km/h) or cycling at 16 km/h [10 mph] as examples of what was needed."

I've often stressed that non-exercise movement, such as standing up at work and walking more, is just as important as a regular fitness routine. On the other hand, this research also points out that having a fitness routine is just as important as staying active and avoiding sitting. As noted by Reuters:"People who sat for eight hours a day but were otherwise active had a lower risk of premature death than people who spent fewer hours sitting but were also less active, suggesting that exercise is particularly important, no matter how many hours a day are spent sitting. The greatest risk of premature death was for people who sat for long periods of time and did not exercise, according to the findings."

In short, you need both. The more time you spend sitting, the more you need to exercise. On the other hand, while sitting less reduces the amount of exercise you need, it does not entirely eliminate your exercise requirement. But just how much movement and regimented exercise do you need? Previous research has provided valuable clues that are worthy of attention.

One impressively large study looking at the exercise and health of 661,000 adults revealed there is in fact a " Goldilocks zone" in which exercise creates the greatest benefit for health and longevity.

As expected, this study confirmed that those who did not exercise at all had the highest risk of premature death. But some of its other findings were more intriguing:

  • Those who exercised but did not meet current exercise recommendations of 150 minutes of moderate exercise per week lowered their risk of early death by 20 percent.
  • Those who met the guidelines of 150 minutes per week of moderate exercise lowered their risk of death by 31 percent during the 14-year study period, compared to those who did not exercise.
  • Tripling the recommended amount of exercise had the greatest benefit. Those who engaged in moderate exercise such as walking for 450 minutes per week (7.5 hours a week or a little over an hour a day) lowered their risk of premature death by 39 percent, compared to non-exercisers.
  • Those who exercised at 10 times above the recommended level only gained the same mortality risk reduction as those who met the guidelines of 150 minutes per week.

A second large-scale study that focused on exercise intensity found that upping the intensity from time to time also had a definitive impact on health and longevity. Here, health survey data from more than 200,000 adults was pooled.

Spending up to 30 percent of the weekly exercise time doing higher intensity exercises led to a 9-percent lower risk of premature death compared to exercising the same amount of time at a consistently moderate pace.

The greatest benefit was found among those who spent more than 30 percent of their exercise time doing high intensity exercises. This group reduced their risk of premature death by an extra 13 percent, compared to those who did an equal amount of low to moderate exercise.

So, to summarize, the data suggests that for optimal health and longevity, you want to exercise for at least 7.5 hours per week (about one hour per day), spending at least 2.25 hours a week (20 minutes a day) doing higher intensity exercises.