If you think that running marathons will help you live a long and healthy life,new research may come as a shock.According to a recent scientific study,people who do a very _ workout are as likely to die as people who do no exercise at all. Scientists in Denmark have been studying over 1,000 joggers  and non-joggers for 12 years.The death rates  from the sample group suggest that people who jog at a moderate  pace two or three times a week for less than two and a half hours in total are least likely to die. The best speed to jog at was found to be about 5 miles per hour.The research suggests that people who jog more than three times a week or at higher speeds of over 7 mph die at the same rate as non-joggers.The scientists think that this is because strenuous exercise causes structural changes to the heart and arteries .Over time,this can cause serious injuries. Peter Schnohr,a researcher in Copenhagen,said,"If your goal is to decrease  risk of death and improve life expectancy,jogging a few times a week at a moderate pace is a good strategy .Anything more is not just unnecessary,and it may be harmful." The implications  of this are that moderate forms of exercise such as tai chi,yoga and brisk walking may be better for us than "iron man" events,triathlons  and long-distance running and cycling.According to Jacob Louis Marott,another researcher in the study,"You don't actually have to do that much to have a good impact  on your health.And perhaps you shouldn't actually do too much". What can be inferred from the text?
No exercise at all is the best choice. More exercise means a healthier life. Marathons runners are least likely to die. Proper exercise contributes to good health.