GETTING INTENSE

Intense exercise has a molecular level impact on the muscles and body that doesn’t occur in milder forms of activity, according to a US study. Although based on mice, the study suggests we must go beyond our comfort zone if we want fitness results.

CRTC2 – a protein released during intense exercise – integrates signals from the adrenalin and calcium pathways and has a direct impact on the muscles being used. The scientists bred mice that would produce much more CRTC2 when faced with a two-week strenuous activity programme, and these modified animals saw a 15 per cent increase in their muscles; metabolic parameters, indicating the amount of fuel available to muscles, improved substantially; and endurance soared – up 103 per cent in the exercise stress test (non-modified mice improved by just 8.5 per cent).

Lead author Michael Conkright says: “The sympathetic nervous system gets turned on during intense exercise, but many had believed this wasn’t specific enough to drive adaptations in exercised muscle. We’ve shown it not only targets specific muscles, but also improves them: the long-term benefits correlate with the workout intensity.”

• The EMBO Journal – The Scripps Research Institute, Florida

We must push ourselves out of our comfort zone to get results / all photos: www.shutterstock.com

CELLULAR CLEAN-UP

US scientists have found that exercise aids a cellular cleaning process in the body known as autophagy.

The research, which was based on mice, showed that exercise increases the ability of skeletal muscle cells to remove damaged components and other cellular debris – the result of daily wear and tear on the body’s cells. In turn, autophagy is vital for muscles to adapt to exercise – and for the body to receive the health benefits of working out.

A cell recycles some components to help keep the rest of itself alive, but when it’s starved or under physiological stress – like exercise – the autophagy process speeds up. Without this process, cells can become blocked, malfunction or die. Some scientists are even beginning to link faulty autophagy function to diseases such as diabetes, cancer and Alzheimer’s. It’s thought the slowing of this mechanism as we get older also plays a part in the ageing process.

The research could also shed light on why some people see little benefit from exercise: if there’s a problem with the cellular cleaning process, the muscle may not be able to adapt to exercise and improve performance. In turn, this could impact the effect of exercise in dealing with metabolic diseases such as diabetes.

• The FASEB Journal – University of Virginia School of Medicine, US

Exercise aids cellular cleaning, which in turn helps the body deal with metabolic diseases / all photos: www.shutterstock.com

BRAIN TRAINING

The brain could potentially be retrained to prefer healthy foods, helping people with weight loss and healthy eating plans, according to a small-scale pilot study.

The study observed how the brain’s reward system responds to healthy and unhealthy food, by looking at a part of our brain (the striatum) that seemingly gives us rewards by releasing chemicals such as dopamine in anticipation of our consumption of food.

For the study, scientists followed 13 healthy but overweight/obese men and women, who were part of a randomised trial of a weight-loss intervention over a six-month period. This saw them randomly separated into groups, with one set taking part in a workplace diet known as the iDiet, while the others were told to take no dieting steps at all. MRI scans at the start and the end of the six months established how the reward section of participants’ brains reacted to dietary and food intake measures.

Those who followed the iDiet – which sought to educate and allow people to reduce calorie intake and eat healthier foods – not only lost weight, but the striatum was also more active when they were shown low-calorie foods. It also demonstrated less of a response when shown high-calorie foods after the six-month period. When compared with the control group, the iDiet participants also showed a greater increase in desire to consume the low-calorie foods and a greater reduction in desire to consume high-calorie food items.

• Nutrition & Diabetes – led by Harvard Medical School, US

The brain can be retrained to prefer healthy foods / all photos: www.shutterstock.com

EXERCISE MOTIVATION

Scientists may have discovered the part of the brain responsible for exercise motivation: the research concluded that the dorsal medial habenula section of the brain controls the desire to exercise in mice.

The scientists genetically engineered a group of mice that had the signals blocked from their dorsal medial habenula. This group of mice became lethargic and ran far less than typical mice, and also lost their preference for drinking sugary water.

In another group of mice, scientists were able to activate the dorsal medial habenula using optogenetics, with these mice given the choice of running on two different wheels – only one of which activated the habenula region. These mice preferred to turn the wheel that stimulated the dorsal medial habenula, creating a link between rewards for specific behaviours and actions.

The findings could prove particularly pertinent given that the structure of the habenula is similar in humans and rodents: if a link is found in the human brain too, gym-goers could potentially unlock the key to more motivation in the gym.

• Journal of Neuroscience – Seattle Children’s Research Institute’s Centre for Integrative Brain Research / University of Washington

Have scientists discovered the part of the brain that drives exercise motivation? / all photos: www.shutterstock.com

MORE GAIN, LESS PAIN

The longer we exercise, the more tolerance we may have towards pain, potentially showing how physical activity can impact perceptions of discomfort.

Previous research has found exercise can help provide brief but concentrated relief for pain, as the body releases natural opiates after activity. However, there has been limited research on the longer-term impact exercise has on our tolerance of pain.

Researchers asked 12 young and healthy but inactive adults, who expressed interest in exercising, to take part in the research. Another group of 12 people – of a similar age and comparable inactivity levels – preferred not to exercise.

The groups were then invited to a lab where their pain thresholds were tested. The groups were then sent away for six weeks to get back on with their daily routines, with the group interested in exercise placed on a programme of moderate activity. After six weeks, those who had improved their fitness through exercise showed a greater tolerance to pain; they felt pain at the same point as before, but were now able to tolerate it for longer.

The research could help provide evidence that physical activity can be used to ease the symptoms of chronic pain.

• Medicine & Science in Sports & Exercise – University of New South Wales and Neuroscience Research Australia

Physical activity could be used to ease chronic pain / all photos: www.shutterstock.com

EXPANDING WAISTLINE, SHRINKING BRAIN?

Obesity could have an impact on how smart we are, according to research conducted on mice which showed how fat may cloud cognitive processes.

Scientists monitored a group of obese mice that housed high levels of a chemical substance known as interleukin 1, which is created from fat cells and can lead to inflammation. This was the case in the brains of the mice, with the chemical having seeped into the hippocampus – an area in the brain responsible for learning capabilities and memory.

The obese mice tested poorly during cognitive tests. The scientists then conducted a small liposuction procedure on the obese mice to remove fat, which led to the specimens performing much better on the same cognitive tests they had taken before the removal of the fat. Finally, the researchers placed fat pads inside leaner mice, with the animals performing worse than they had done in their previous brain function tests.
The obese mice were then placed on a daily exercise regime and compared to a group of sedentary mice after three months. Despite remaining the same weight as those that didn’t take part in exercise, the obese mice had gained lean muscle and lost fat, and had begun to outperform the non-active mice in cognitive tests.

• Georgia Regents University, US

Obesity could impact how smart we are / all photos: www.shutterstock.com

CASH BACK

A UK study has suggested that people’s motivation to exercise would rise if they were offered a financial reward for being active.

The research focused on 16 previous studies in which people had been given incentives to improve their health in some way, such as by taking up physical activity, quitting smoking or attending vaccination/disease screening sessions. The studies involved a total of more than 30,000 participants.

Overall, financial incentives ranged from £3 (US$5.16) for having a flu vaccination to £467 (US$786) for taking part in an employee scheme to give up smoking for a year. Yet even in the flu vaccination study, where the reward was just £3, people were 50 per cent more likely to change their behaviour. In fact, it was found that larger incentives were no more effective than smaller monetary rewards in influencing people’s behaviour.

Financial penalties for not succeeding in the task were also found to work. In these studies, participants had to hand over a set amount of money which they knew they wouldn’t get back if they didn’t fulfil the health behaviour requirements.

• PLOS ONE – University of Newcastle, UK

Small rewards can positively change people’s behaviour / all photos: www.shutterstock.com

FLAVOUR BEHAVIOUR

Taste plays a crucial role in regulating the appetite and dictating what we choose to eat and how much we consume. And now a study – which looked at the cells on the tongue that come into initial contact with food – suggests our ability to taste, and for our taste buds to detect sweetness, could be altered in severely overweight people.

Lead scientist Kathryn Medler says: “What we see is that, even at the first step in the taste pathway, the taste receptor cells themselves are affected by obesity.”

The study compared 25 normal mice with another 25 that had been fed a high-fat diet and became obese. The scientists then presented the mice with different tasting solutions – sweet and savoury – and measured their response. In the obese mice, there were a lower number of taste cells that were able to detect sweetness. What’s more, among the obese mice, any tongue cells that did respond to the sweet solution reacted relatively weakly compared to the tongue cells in the normal weight mice.

Medler believes not being able to detect sweetness may lead obese mice to eat more so they can get the same taste effect.

• PLOS ONE – University of Buffalo, New York, US

Obesity may lessen our ability to detect sweetness / all photos: www.shutterstock.com