We need to embrace gravity as a stimulus and engage with it if we want our bodies to age well, writes CLAIRE O'CONNELL
IT MIGHT feel like gravity is our sworn enemy as we advance in years. We lament as skin starts to sag and certain body parts move south, and gravity-defying actions that used to pose little challenge in youth – like bouncing up out of a chair or charging up the stairs – increasingly feel like we are being pulled to the centre of the earth.
But a scientist who has spent decades researching with Nasa believes we shouldn’t give in and take a comfy seat – instead we need to embrace gravity as a stimulus and actively engage with it to help our bodies age in good health. In other words: gravity is your friend.
Dr Joan Vernikos, who was in Dublin City University last week, started looking into the effects of space travel on the human body in the 1960s and her interest soon turned to the effects of gravity and its effects on humans.
“If you think about it, we know it is very important to plants. Every child knows at school the experiment of turning the plant on the side and it grows up and down,” she says.
But she notes that most doctors would probably look at you blankly if you asked them about the effects of gravity on human health. “There is nothing in text books about gravity, right to this day,” she says.
Yet a lack of gravity appears to have a profound physical effect on astronauts in space. Research shows that spending time in space increases the rate of bone loss, and once back on terra firma, astronauts can transiently experience difficulties such as passing out when they stand up.
Given the relatively small numbers of humans going into space, ground-based experiments have also been used to simulate the effects of microgravity so researchers can monitor its effects.
Healthy participants sign up for prolonged bed-rest experiments, because lying down decreases the length of the axis in the body through which gravity can act. To add to the fun, they may lie at an incline with the feet up and the head slightly down, which is considered an even better model. Volunteers could spend several months in this position to help scientists figure out the long-term effects of giving your body a break from gravity.
“The first 20 minutes are a bit uncomfortable because the blood rushes to your head,” says Vernikos, who headed Nasa’s life sciences division in the 1990s. “But after 20 minutes it feels normal.”
One of her own bed-rest experiments looked at how often someone might need to engage more fully with gravity to address the internal ageing process that a lack of the stimulus seems to accelerate.
“I was curious about that and what does it take if you are lying in bed 24 hours a day, how many times do you need to be standing up during those 24 hours to prevent the changes? The results there showed that you need at least 16 times a day of going from lying down to standing up to maintain the blood pressure.”
So how can those of us on earth and not on enforced bed rest use the findings, particularly as we get older and possibly more sedentary in our habits?
“When people ask me how can you use gravity I say watch a child, be a child again. Swing on a swing, a wonderful vestibular exercise, hang upside down, hang over the side of the bed like we used to as children,” says Vernikos.
“Where did it go? We got used to sitting down – and we wonder why our brain doesn’t get any blood. Yoga comes close and I don’t mean standing on your head, I mean the various orientations that you expose your body to; they really come the closest to being a child again.”
The thrills of rollercoasters, sports cars and bungee jumps also use gravity, but for more everyday applications, relatively simple actions can help, such as taking the stairs and getting dressed standing up, according to Vernikos, who co-authored The G-connection: Harness Gravity and Reverse Aging.
“Stand up, get out of your chair. And how often? I think it’s every 20 minutes,” she says, outlining a few of her own strategies. “When I talk on the telephone I pace, I pace and I think. I try to get out of my chair as often as possible and I try to get out of my chair unaided from wherever I am sitting.”
She also stresses the need to build movement into the regular day.
“It’s incongruous to me that we should think half-an-hour of exercise in the gym or anywhere should make up for all of the inactivity for the rest of the day,” she says.
“It’s good, it’s wonderful to exercise, but the foundation of movement is in the non-exercise activities we do all day throughout the day.
“Try to structure your day so you have constant activity all day long, every day, 365 days a year. It’s like brushing your teeth, turning using gravity into a habit so it becomes like second nature.”
Since retiring from Nasa, Vernikos has acted as a space consultant for many projects, and she visited Dublin last week to work with a European Space Agency topical team led by Dr Donal O’Gorman at DCU.
They are using the bed-rest model to identify early “biomarkers” of metabolic change in the simulated microgravity environment.
“It is becoming clearer that the underlying common mechanism for these age-like changes is metabolic, involving possibly both oxidative and inflammation mechanisms,” says Vernikos.
“The Dublin work on muscle is at the forefront of what is happening and Donal [O’Gorman] is sharp enough to realise that the telescoping of changes in space or in bed is a valuable research tool, not to mention its potential applications to the rest of us.”
