Microgravity makes it tricky to do simple tasks like eating, using the toilet and showering, so it is no wonder that performing CPR on someone whose heart stops beating in space is an extremely demanding procedure. But a mechanical device could do the job more effectively, tests carried out in simulated microgravity suggest.

On Earth, one’s weight and strength are used to compress the patient’s chest. But in space, things are different, as weight becomes virtually meaningless.

±·´ˇł§´ˇâ€™s CPR protocol for the International Space Station demands that you wedge yourself and the patient between two hard surfaces, do a handstand on their chest and push with your legs to provide compression.

In search of a better way, at the University of Lorraine in France and his colleagues tested various CPR methods in an Airbus A310 aeroplane flying parabolic curves, a manoeuvre that creates 22 seconds of microgravity. They also tested three different chest compression machines that are commonly used in cramped environments on Earth, such as in the back of air ambulance helicopters.

All the methods were applied to a training dummy and the depths of chest compression achieved were carefully monitored. The European Resuscitation Council says a depth of at least 50 millimetres is necessary to be effective: in the tests, the best mechanical device achieved 53 millimetres, but the handstand method only achieved 34.5 millimetres.

The research will be presented at the European Society of Cardiology Congress in Madrid on 31 August. Reynette and his colleagues said in a press release that they hope their findings will influence future guidelines on CPR in space.

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at University College London says the current method for CPR in space is difficult to perform and ripe for improvement. “If you were doing this in zero gravity or in a space station for some reason, things have probably gone very wrong and the prognosis is probably not great,” he says. “This new method seems to address that.”

As space travel becomes more common and astronauts aren’t all highly selected and extremely fit people, the likelihood of cardiac incidents in orbit will grow larger, says Parkhurst. “Leaving Earth’s atmosphere, just the stress of those moments in the rocket, is extremely hard on the heart. And living long-term in space is extremely hard on cardiovascular systems. So it’s bound to happen,” he says.

A NASA spokesperson said in a statement: “Manual compressions remain the current CPR procedure aboard the International Space Station. NASA mitigates the risk of needing CPR through extensive medical screening of astronauts and robust engineering safeguards. NASA has not conducted dedicated studies on the use of CPR machines in microgravity; however, our medical team closely follows all emerging research and findings and will continue to do so as the agency prepares for future human exploration missions to the Moon, Mars, and beyond.”

Watching an athlete at their peak is thrilling. Fulfilling one’s own athletic potential, not so much. Getting fit is hard and painful – or so we assume.

But that isn’t necessarily the case. In fact, research shows that anyone just starting to exercise more than they are used to will see improvements surprisingly quickly, regardless of the workout they choose. Better yet is the discovery that there are ways to speed up the fitness journey.

The key to improving fitness is, in essence, simple. You need to exceed your “habitual load”, which is a fancy way of saying doing more activity than you are accustomed to. This will stress your body and force it to adapt.

When it comes to starting cardio exercise as a beginner, “one of the first things that happens is you get more blood volume”, says  at the University of Michigan. Within 24 hours of working out, this increases by up to due to water retention, which increases the amount of blood plasma, boosting the amount of oxygen that can be supplied to the muscles. After two weeks of training, peak blood volume is normally reached, which is about .

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Energy-producing structures within our cells called mitochondria become more numerous and efficient around this time as well. Small blood vessels known as capillaries begin rapidly proliferating within muscles, too, improving the body’s ability to deliver oxygen to tissues. One found that capillary density expanded by about 20 per cent after two months of a cycle training programme.

These shifts enhance the maximum rate at which the body can use oxygen, a measure known as VO2 max, says at the University of Glasgow, UK. Changes in VO2 max typically occur around six to eight weeks into training. By the third month, it can improve by approximately 10 per cent, he says.

Getting stronger

Muscle also adapts rapidly. within muscles involved in regulating inflammation and removing waste products that accumulate as a result of the stress of exercising. It doesn’t take long to build muscle strength either, at least if you are a beginner. “Everyone gets stronger in their first three weeks because your nervous system learns how to talk to your muscles better,” says Lane. With repetition, the nerve signals from the brain get quicker, and muscles become better at responding to them, generating greater force more rapidly, says Gray.

Exercising also builds brawn by tearing muscle fibres, allowing them to build back stronger. In a sense, you literally become “ripped”. This takes a bit longer, though, so the greatest improvements in muscle size and strength don’t happen

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All of this suggests that exercise should feel a bit easier within two to three months of your first workout. But several factors mean this varies from person to person. The most significant influence is genetics. Our genes determine about half our aerobic fitness, says Lane. “Some people, no matter how much they train, their VO2 max won’t shift very much,” says Gray. “Then, you’ll get the very annoying people that will do the same training as you and their VO2 max will fly off the charts.”

Age is another factor, with . Prior physical activity makes a difference, too, as people who have previously trained are able to rebuild muscle faster than those who are just starting out.

A wide range of exercises can improve fitness within a few months, provided they are done three to five times a week for about 30 to 60 minutes. For instance, 12 weeks of endurance training such as cycling , roughly the same as a strength training programme of the same duration. However, one regime seems to trounce all others in terms of getting fit quick – both from an aerobic and strength perspective – by stressing our physiology in just the right way to induce maximal adaptation.

High-intensity interval training

High-intensity interval training (HIIT) involves exercising at near maximum effort in repeated bursts of up to a minute, with short rests in between. This regime was devised in the 1990s by Izumi Tabata and his colleagues at the National Institute of Fitness and Sports in Kanoya, Japan. They showed that a 4-minute workout, with repeated cycles of 20 seconds of intense work then 10 seconds of rest, done five days a week for six weeks resulted in than moderate, hour-long workouts done over the same time frame.

Since then, many trials have confirmed the power of HIIT. “If you want a quick increase [in fitness] over four to six weeks, purely intervals would do the job,” says Lane. The key is working as hard as you can during the intense intervals. Just six HIIT sessions over two weeks significantly improves VO2 max and endurance capacity, but, remarkably, a  found similar improvements could be achieved if these HIIT sessions were squeezed into a five-day period.

at the Norwegian School of Sport Sciences in Oslo says beginners should start with two to three HIIT sessions per week. You can intersperse these with longer-duration endurance activities, such as jogging or swimming, to further boost results, he says. Once you notice that your strength has plateaued with HIIT, you can add two or three full-body strength-training sessions, says Lane.

However, the best exercise is ultimately the one you will be able to stick with, not necessarily the one that leads to the quickest improvements. “We sometimes get in the weeds with what is the perfect plan, but I think for most people, we just need to get out there and get moving,” says Gray.

The trick is to continuously challenge yourself. If you do, you may be surprised to discover your own peak performance.