Regular, high-impact exercise linked to increased BMD in young women
MedWire News: Regular, high-impact exercise, such as jogging or spinning, is associated with increased bone mineral density (BMD) in women aged 25 years, show study findings.
Current thinking suggests that in women, peak bone mass (PBM) is attained between the age of 16 and 19 at the hip, and just after the age of 30 at the lumbar spine. "A one standard deviation increase in PBM has the potential to decrease the risk of fracture by as much as 50%," say Kristina Akesson (Lund University, Malmö, Sweden) and colleagues.
To evaluate the effects of recreational exercise on BMD and changes in pattern over time, the researchers measured BMD at the total body (TB-BMD), femoral neck (FN-BMD), trochanter (TR-BMD), and spine (LS-BMD) among 1061 women aged 25 years. Women completed a questionnaire to assess levels of physical activity.
Over 50% of women reported exercising on a regular basis, with running, strength training, aerobics, and spinning most common. Furthermore, 70% of women participated in at least one activity during the year.
Women who participated in regular, high-impact exercise - according to either their recreational activity level (RAL) or peak strain score (PSS) - had significantly higher FN-BMD (by 2.56 and 2.93%, respectively), TR-BMD (3.33 and 3.47%), and LS-BMD (1.52 and 2.11%) than those who with low-to-moderate exercise levels by each score.
When the team assessed the effect of physical activity on skeletal integrity according to combined scores for RAL and PSS (COMB-RP), they found that BMD was greatest at all measured sites at the highest exercise impact levels. Women with both high RAL and PSS scores (high-COMB-RP) showed the greatest gains in BMD (FN 4.7%, TR 5.5%, LS 3.1% relative to low-COMB-RP), despite having significantly lower bodyweight than those with low levels of activity.
The study also revealed that jogging and spinning were the most beneficial for increasing TR- and FN-BMD, with relative increases of 8.5% and 7.2% for jogging and 6.4% and 7.2% for spinning, respectively, compared with no activity.
Assessment of previous levels of physical activity and attitudes towards exercise revealed that the most active women enjoyed exercising when at school considerably more than the least active did. Furthermore, women with low-COMB-RP scores showed a significant decline in their activity levels between school and age 25 years, with 79% reporting that they had been more active previously compared with 46% of women in the high-COMB-RP group.
"It is important already during the school years not only to encourage physical activity but to make it enjoyable, since it will promote habitual continuous physical exercise later in life, resulting in advantageous effects on peak bone mass and possibly on other organ systems," conclude the authors in the journal Osteoporosis International.
MedWire (http://www.medwire-news.md/) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2012
By Ingrid Grasmo