Longevity Briefs: Walk Slowly, Die Sooner?

Getting your Trinity Audio player ready...

Longevity briefs provides a short summary of novel research in biology, medicine, or biotechnology that caught the attention of our researchers in Oxford, due to its potential to improve our health, wellbeing, and longevity.

The problem:

We all know that regular exercise is good for us, but studies repeatedly show that even small amounts of low-intensity exercise (such as a 20-minute walk every day) have surprisingly large benefits on health and life expectancy compared to no exercise at all. Of course, a faster walking pace will produce greater benefits for the same duration, but by how much? This study provides an answer to that question.

The discovery:

Between 2002 and 2009, researchers recruited nearly 85,000 individuals from southeastern US states, predominantly low-income and over two-thirds black. They chose this population because previous studies predominantly focused on wealthier white populations. At the beginning of the study, participants provided information on their daily walking pace (slow vs. fast) and time spent walking, along with other important lifestyle details (like smoking, alcohol, diet quality, and other physical activity). They were then followed up until the end of 2022.

As expected, walking was associated with reduced mortality, but walking pace had a huge impact on extent of this reduction. Fast walking for 30 minutes or less per day was associated with a nearly 20% reduction in total mortality compared to no walking at all. On the other hand, more than 3 hours of slow walking per day was associated with a mere 4% reduction in mortality, which did not quite attain statistical significance (i.e. it could have been due to chance).

Table showing hazard ratios (HR) for all-cause mortality for different durations of fast or slow walking. Hazard ratio is the rate of deaths relative to the reference, which in this case is people who did not walk at all. For example, an HR of 0.82 for 0-30 minutes of fast walking means that for every 100 deaths among people who do no fast walking, there were 82 deaths among those who walked for 0-30 minutes (an 18% reduction). The three different columns for HR in this table correspond to different levels of adjustment for confounding factors, with the rightmost column having the most confounders adjusted for.
*Daily Walking and Mortality in Racially and Socioeconomically Diverse U.S. Adults*

The benefits of fast walking were observed after having controlled for other physical activity, meaning fast walking still provided additional protection for participants who were active in other ways. Participants with existing health conditions (like hypertension or diabetes) saw larger risk reductions, but everyone benefited from fast walking regardless of their baseline health.

The implications:

This study once again shows how it really doesn’t take much effort to significantly lower you risk of death. Walking is a form of exercise that doesn’t cost anything, doesn’t require training and can be easily combined with other daily tasks. The study also suggests that walking speed is more valuable than duration when it comes to reducing mortality risk.

This study benefits from having a long follow-up period and a large sample size from a typically underrepresented population. However, it also has some notable weaknesses. The walking data was self-reported, which makes the data less reliable than objective measurements from accelerometers, which are much easier to obtain now that smartphones are commonplace. Participants only reported their walking habits once at the start of the study, so their habits could have changed later on. Furthermore, it’s impossible to prove cause and effect in an observational study such as this one – people who walk more slowly might do so because they are less fit to begin with for reasons that were not accounted for.