Will the average person need to exercise during a commercial spaceflight?

This article was first published by The Conversation. Space.com's Expert voices: Op-Ed and Insights was contributed by the publication.Andrew Winnard is the Lead for the Aerospace Medicine Systematic Review Group, and Lecturer at Northumbria University in NewcastleClaire Bruce-Martin, Senior Lecturer, Sport, Exercise, and Rehabilitation, Northumbria University, NewcastleJonathan Michael Laws is a PhD researcher at Northumbria University in Newcastle.Nick Caplan, Northumbria University's Newcastle Professor of Aerospace Medicine and RehabilitationSpaceX, owned by Elon Musk, plans to launch the first private mission into space without professional astronauts. Jared Isaacman (billionaire entrepreneur) will be the commander of the mission and chartered it. He will also spend two to four days orbiting Earth with three others in the SpaceX Crew Dragon capsule.Although Crew Dragon's short mission will not have any significant impact on passengers' health, the capsules will soon travel on longer trips which could have an enormous effect on someone's health. Space missions can reduce astronauts' bone density by between 1% and 1.5% per month, and they can weaken movement and postural muscle. The space gravity doesn't force the heart to pump against it, so even the heart shrinks. The time it takes for these changes to occur varies depending on how many exercises are performed and how often they are done. These changes will not occur if you don't exercise for 14 days. Professional astronauts also use space exercise equipment to maintain their muscles.Capsular spacecraft like NASA's Orion and Crew Dragon will not have enough space to store large equipment. This will limit the activities that passengers can do. This will have an unknown effect on the health of spaceflight passengers. Northumbria's Aerospace Medicine Systematic Review Group is trying to find out.Related: Space astronauts offer isolation training tips (video)There is space to moveAround 33,000 cubic feet (932 cube meters) of space is available for the International Space Station (ISS). This volume is equivalent to that of a Boeing 747. Two-thirds of the space is used to store and equip equipment, such as a treadmill and a resistance exercise machine.The ISS life support system maintains a healthy environment by controlling oxygen, heat, and moisture levels in the cabin. It also allows astronauts to exercise for up to two and a quarter hours per day, six days a weeks, without excessive heat or carbon dioxide buildup.Crew Dragon and Orion have approximately 320 cubic feet (9 meters) of living space, with approximately 177 cubic feet (5 meters) of this being usable for exercise. This would be similar to going on a four day trip with three friends in a small campervan. You wouldn't be able move much and you couldn't leave the cabin.The equipment used by space station astronauts is too large and heavy to fit on a capsule. One exercise device will be allowed on a capsular spacecraft. This device should be the size of a shoebox, not more than 10.6kg. An Orion spacecraft could accommodate a flywheel exercise device. This disc-based device provides resistance for a variety of exercises, such as a rowing machine.Capsular spacecraft passengers would have to break up their exercise sessions into multiple sessions daily in order to be able to exercise as many times as the ISS astronauts. If only one device is available, this could mean that the entire crew would need to exercise for up to 18 hours each day. The filtration systems could also be used to remove additional heat, moisture, and carbon dioxide from the exercise.Space-based astronauts do exercises to preserve bone density and muscle. (Image credit NASA Marshall Space Flight Center Follow/ Flickr CC BY -NCNot exercisingWhat if the passengers did not exercise? We need to study bed-rest studies in order to understand the potential effects. Bed rest without leaving Earth is a great way to simulate the effects of spaceflight. Bed rest that is too strict can also cause similar deconditioning (the loss of physical function) to spaceflight.Research has shown that mild muscle wasting can occur in space for seven days if there is no exercise. Crew Dragon passengers will likely experience minimal muscle wasting if they do not exercise during their two to four-day mission. Your body requires some stress almost every day in order to function well. Any muscle wasting will be easily reversed once they return to Earth. All that is required to do this is to be back in normal gravity, hold themselves up, and continue their daily activities.For longer missions like a five-day orbit to the moon or a Mars orbit that may take 200 days, it will be crucial to exercise. Muscle power, endurance, and volume decrease after seven days in space. After 14 days, muscle power, volume and endurance begin to decline. Without exercise, large changes such as difficulty standing can occur within 28-35 days.Although a moon trip takes less than seven days, the Moon's reduced gravity (one-sixth of Earths gravity), is unlikely to make it possible for the human body to stay healthy on its return journey. Crew members will need to train for a round trip to the Moon in order to return safely to Earth. Astronauts who spend more than a few days on the moon will need to exercise in order to maintain their health and strength. These types of missions will be reserved for professional astronauts for the moment.It is not clear yet what protocol and exercise devices will be made available to people who are stationed in spacecrafts with longer durations. Our research group is currently investigating which exercises are most effective in protecting against space-related physical changes. To make exercising easier, larger habitat modules could be attached to spacecraft in deep space.Space adaptation syndrome can also affect commercial spaceflight passengers. This causes motion sickness. It can affect 60% to 80% of space travelers during their first two-three days on their mission. It can also cause stuffy sinuses and headaches due to fluids shifting upwards. Back pain may also occur as their spines lengthen due to lack of gravity. These problems are minor and will disappear after the mission.Crew Dragons missions will hopefully become more frequent, cheaper, and longer over time. However, as space travel becomes more feasible and longer missions are made, it is important that passengers exercise regularly to avoid any adverse effects on their health.This article was republished by The Conversation under Creative Commons. You can read the original article.Follow Expert Voices to keep up with the debates and issues. You can also join the conversation on Facebook and Twitter. These views are the author's and may not reflect those of the publisher.