Walking is regarded to be an important form of physical activity for individuals belonging to all age groups.
Several studies have linked walking with improved physical fitness and decreased risk of cardiovascular disease. Compared to slow pace walkers, brisk walkers exhibit greater life expectancy.
UK Biobank measured physical activity using an accelerometer and revealed that ten minutes of brisk walking a day could bring about a longer life expectancy. Additionally, a genome-wide association study (GWAS), based on self-reported walking pace, revealed the presence of seventy independent single nucleotide polymorphisms (SNPs), which is greater than accelerometer-assessed studies on physical activities of the same cohort.
Researchers indicated that walking pace also reflects upon many underlying conditions of an individual, including musculoskeletal health, lung capacity, motor control, cardiorespiratory fitness, and mental health. These factors are also linked with the biological age and physiological conditions of an individual. Therefore, the walking pace serves as a modulator for biological age and a marker for many physiological conditions.
Even though the link between leucocyte telomere length (LTL) and disease manifestation is complicated, LTL plays an important role as a marker of biological age. Scientists use LTL as an indicator for many high-risk age-related diseases, such as cancers and coronary artery disease.
DNA-Protein complexes that are present at the tips of chromosomes are known as telomeres. The main functions of telomeres are to protect the end of the chromosome from damage and prevent an end-to-end fusion. It also prevents abnormal recombination of DNA strands, thereby, helping maintain genomic stability.
Scientists have stated that the components of DNA shorten progressively with each life cycle. Previous studies have also reported that telomere shortening occurs due to inflammation and oxidative stress. Typically, the length of telomeres is measured in leucocytes (LTL), which reflects the senescent conditions of circulating cells. This measurement also indicates the immune status of an individual.
Although few studies have linked greater physical activities and cardiorespiratory fitness with longer LTL, not much evidence is available to establish the association between walking pace and LTL. Therefore, recently scientists addressed this gap in research and investigated the link between self-reported walking pace and LTL among middle-aged adults. This study has been recently published in Communications Biology.
About the study
In this study, scientists utilized a large prospective cohort, containing participants of the UK Biobank, which was designed to support biomedical analysis. They utilized previously used genetic instruments for both walking pace and LTL so that they can exploit bi-directional Mendelian randomization (MR) analyses for their analysis. This helped researchers to differentiate between causal and important associations observed in this study. The authors of this study hypothesized that brisk walkers possess longer LTL.
Based on accelerometer-assisted data on physical activity, scientists revealed that compared to total activities, individuals who performed higher intensity activities showed a robust relationship with LTL. Additionally, the bi-directional MR analyses also supported a causal relationship between walking pace and LTL, and not the other way around.
The MR results reflected the limited availability of high-quality studies. However, the result of the current study is in line with reports of a previous non-randomized study, which showed that individuals under long-term endurance training were linked with decreased LTL erosion, compared to non-exercising healthy individuals.
Similarly, another study conducted a randomized controlled trial and revealed forty minutes of moderate level aerobic exercise three to five times a week could substantially reduce LTL erosion, compared to the control group. These studies suggested the possibility of mechanisms that link physical activity to biological aging. The MR analysis revealed the difference in LTL between slow and brisk walkers.
Strengths and limitations
One of the key strengths of this study is its large, well-phenotyped cohort with superior LTL data. In this study, the authors emphasized the importance of walking pace and recommended that brisk walking pace is an important determining factor of LTL, which supports the overall health condition of an individual.
This study also has some limitations, including a one-time estimation of LTL. Additionally, the current study does not perform any longitudinal analysis, which is essential to determine the link between physical activity and LTL attrition. However, the authors indicated that previous longitudinal studies of LTL revealed marginal changes, within an adult, occur over time. Another limitation of this study is its cohort containing participants of UK Biobank who are relatively healthier than the general population.
In the future, more studies are required to analyze other benefits of brisk walking for the health status of an individual. More studies are needed to elucidate whether behavioral interventions focused on enhancing walking pace or performing intense physical activities would cause reduced LTL erosion. In the future, the relationship between LTL and different age groups must also be characterized.