Running may improve long-term bone health more effectively than non weight-bearing activities like cycling or swimming, according to new study that measured the hormones of mountain ultramarathon runners.
The Italian research, presented at the recent European Congress of Endocrinology, focused on two vital bone constituents as well as hormones associated with energy regulation. Osteocalcin and P1NP are two proteins associated with bone formation and their levels in blood are an indicator of bone health.
Glucagon, leptin and insulin are hormones involved in regulating metabolism and indicate the body´s energy needs. Increasing glucagon levels indicate an energy demand, whilst increasing insulin and leptin levels indicate adequate or excessive energy levels, the European Society of Endocrinology explained.
For the study, the researchers measured these three hormones as well as levels of osteocalcin and P1NP in 17 trained runners before and after a 65-km mountain ultramarathon run. The results were compared to the hormones and bone constituents of 12 adults of the same age who did not run the race but did low to moderate physical exercise.
Compared to the control group, ultramarathon runners had higher levels of glucagon and lower levels of leptin and insulin when finishing the race. According to the European Society of Endocrinology, the falling levels of insulin among the runners were linked to similarly falling levels of both osteocalcin and P1NP — suggesting that athletes may be diverting energy from bone formation to power the high-energy demands of their metabolism.
However, the runners had higher P1NP levels at rest compared to controls, suggesting that they may divert energy from bones during racing but have a net gain in bone health in the long term.
In contrast, an earlier study by the same team found that cyclists racing in ultra-endurance conditions suffered chronic bone resorption — a condition in which calcium from bone is released into the blood stream, weakening bones.
“The every-day man and woman needs to exercise moderately to maintain health,” commented Dr Giovanni Lombardi, lead author of the study. “However, our findings suggest that those at risk of weaker bones might want to take up running rather than swimming or cycling.”
The role of osteocalcin may help explain the effect of different exercises on bone formation, Dr Lombardi explained.
“Previous studies have shown that osteocalcin communicates with beta cells in the pancreas, which regulate the body´s glucose metabolism,” he said. “Because running exerts a higher physical load on bone than swimming or cycling, it could be that these forces stimulate bone tissue to signal to the pancreas to help meet its energy needs in the long term.”
“Our work has shown that bones aren´t just lying idle, but are actively communicating with other organs and tissues to drive the body´s energy needs,” Dr Lombardi added. “We often find that metabolic conditions and fracture risks are linked to the same underlying condition, so the more we learn about the interaction between bones and body metabolism, the better we will understand complex but important diseases such as diabetes and osteoporosis.”