New Studies Link Higher Daily Steps to Lower Health Risks, Even for Sedentary Individuals

Two recent observational studies, published in separate scientific journals, have found associations between higher daily step counts and lower risks of mortality and several chronic diseases, including for individuals with high levels of sedentary time. The research suggests step count is a practical metric for physical activity, though the findings also indicate that physical activity may not completely offset all risks associated with prolonged sitting.

Summary of Key Findings: A study in the British Journal of Sports Medicine found that any amount of daily steps above 2,200 was associated with lower mortality and cardiovascular disease risk, with optimal benefits observed at 9,000 to 10,000 steps. A separate, larger study in Nature Communications concluded that adding between 1,700 and 5,500 steps per day could reduce the risk for specific chronic conditions in people who are sedentary for 8 to 14 hours daily, though it did not show the same effect for coronary heart disease and heart failure.

Study 1: Step Count, Mortality, and Cardiovascular Disease

Publication & Data Source:
Research published in the British Journal of Sports Medicine analyzed accelerometer data from 72,174 participants in the UK Biobank, tracked over an average of 6.9 years.

Participant Profile:

• Average daily steps: 6,222
• Average daily sedentary time: 10.6 hours

Key Findings:

• The lowest activity group (approximately 2,200 steps daily) served as the baseline.
• Over the follow-up period, 1,633 deaths and 6,190 cardiovascular disease cases were recorded.
• After statistical adjustments, the greatest reduction in risk was observed among those taking 9,000 to 10,000 steps daily, showing a 39% lower risk of death and a 21% lower risk of cardiovascular disease compared to the baseline.
• Approximately half of this total risk reduction was achieved with 4,000 to 4,500 steps daily.
• These benefits were observed regardless of whether participants had high (10.5+ hours) or low daily sedentary time.

Researcher Statements:

Lead author Dr. Matthew Ahmadi stated that while walking is not a complete solution for excessive sitting, "all movement matters" and increasing daily steps can help offset health consequences of unavoidable sedentary time.

Senior author Professor Emmanuel Stamatakis noted that step count is a tangible measure that could help inform future device-based physical activity guidelines.

Limitations:

• Observational design prevents proof of cause and effect.
• Step counts were measured at a single point in time.
• Unmeasured factors could influence the observed associations.

Study 2: Steps, Sedentary Time, and Chronic Disease Risk

Publication & Data Source:
Research published in Nature Communications on April 7, 2024, analyzed over 13 million days of Fitbit data from 15,327 adult participants in the U.S. National Institutes of Health's (NIH) All of Us Research Program. Data was linked to electronic health records.

Participant Profile:

• Median daily steps: 7,416
• Median daily sedentary time: 11.6 hours
• Median monitoring period: 3.7 years
• The cohort was predominantly White and female, with a median age of 52.

Key Findings on Sedentary Time:

• Increased sedentary time was associated with a higher risk for 11 out of 12 chronic diseases examined. The conditions included:
  • Obesity
  • Diabetes mellitus
  • Hypertension
  • Coronary artery disease
  • Heart failure
  • Metabolic dysfunction-associated steatotic liver disease (MASLD)
  • Chronic kidney disease
  • Chronic obstructive pulmonary disease (COPD)
  • Major depressive disorder
  • Sleep apnea
  • Atrial fibrillation
• No significant association was found with ischemic stroke.

Key Findings on Step Count Mitigation:

• Higher daily step counts were associated with a reduced risk across all 12 chronic conditions studied.
• For individuals with high sedentary behavior (8-14 hours daily), adding specific numbers of daily steps was associated with reduced risk for several conditions:
  • 1,700 additional steps: Obesity, MASLD
  • 2,200 additional steps: Hypertension, Sleep apnea
  • 5,300 additional steps: Diabetes mellitus
  • 5,500 additional steps: COPD
• The analysis found that adding steps did not mitigate the increased risks for coronary heart disease and heart failure associated with high sedentary time. For these conditions, risk did not return to baseline at any step count between 0 and 20,000.
• The study noted non-linear patterns for some conditions, with risk for hypertension and heart failure stabilizing around 8,000 steps, and risk for coronary artery disease decreasing up to 12,000 steps but rising again at higher step counts.

Research Context & Statements:

• The study used the All of Us database, for which Vanderbilt Health serves as the data coordinating center.
• Corresponding author Dr. Evan Brittain stated the dataset was rare in physical activity literature due to its use of objective device-tracked data rather than self-reporting.

First author Dr. Neil Zheng said step count is an intuitive measure for suggesting lifestyle changes to patients, compared to advising "moderate to vigorous activity minutes."

Limitations:

• The observational data cannot prove causation and raises the possibility of reverse causation.
• The cohort's demographic makeup may affect the generalizability of the results.
• Sedentary time was estimated using proprietary Fitbit algorithms.
• The analysis did not distinguish between continuous versus broken-up periods of sedentary time.

Funding:
Both studies reported receiving support from the National Institutes of Health. The Nature Communications study was supported by grants R21HL172038, R61/R33HL158941, and R01FD007627.