Editing Long-distance running (section)

=== Impact on health ===
<blockquote>"… an evolutionary perspective indicates that we did not evolve to run long distances at fast speeds on a regular basis. As a result, it is unlikely there was a selection for the human body to cope with some of the extreme demands runners place on their bodies."<ref name="extreme">{{Cite book |last=Lieberman |first=Daniel E. |title=The Long Distance Runner's Guide to Injury Prevention and Treatment |date=2017 |publisher=Skyhorse Publishing |editor-last=Waite |editor-first=Brandee L. |pages=2–17 |chapter=History of Distance Running |editor-last2=Krabak |editor-first2=Brian J. |editor-last3=Lipman |editor-first3=Grant S. |chapter-url=https://scholar.harvard.edu/dlieberman/publications/history-distance-running}}</ref>
</blockquote>

The impact of long-distance running on human health is generally positive. Various organs and systems in the human body are improved: bone mineral density is increased,<ref>{{Cite journal |last1=Hagihara |first1=Yoshinobu |last2=Nakajima |first2=Arata |last3=Fukuda |first3=Satoshi |last4=Goto |first4=Sumio |last5=Iida |first5=Haruzo |last6=Yamazaki |first6=Masashi |date=October 2009 |title=Running exercise for short duration increases bone mineral density of loaded long bones in young growing rats |journal=The Tohoku Journal of Experimental Medicine |volume=219 |issue=2 |pages=139–143 |doi=10.1620/tjem.219.139 |issn=1349-3329 |pmid=19776531 |doi-access=free}}</ref> and cholesterol is lowered.<ref>{{Cite journal |last1=Gordon |first1=Benjamin |last2=Chen |first2=Stephen |last3=Durstine |first3=J. Larry |date=July 2014 |title=The effects of exercise training on the traditional lipid profile and beyond |journal=Current Sports Medicine Reports |volume=13 |issue=4 |pages=253–259 |doi=10.1249/JSR.0000000000000073 |issn=1537-8918 |pmid=25014391 |s2cid=10408945|doi-access=free }}</ref>

However, beyond a certain point, negative consequences might occur. Older male runners (45-55) who run more than {{convert|40|mi|km|abbr=off|sp=us}} per week face reduced testosterone levels, although they are still in the normal range.<ref>{{Cite journal |last1=MacKelvie |first1=K |last2=Taunton |first2=J |last3=McKay |first3=H |last4=Khan |first4=K |date=August 2000 |title=Bone mineral density and serum testosterone in chronically trained, high mileage 40–55-year-old male runners |journal=British Journal of Sports Medicine |volume=34 |issue=4 |pages=273–278 |doi=10.1136/bjsm.34.4.273 |issn=0306-3674 |pmc=1724199 |pmid=10953900}}</ref>  Running a marathon lowers testosterone levels by 50% in men and more than doubles cortisol levels for 24 hours.<ref>{{Cite journal |last1=França |first1=Sheyla Carla A. |last2=Neto |first2=Barros |last3=Leite |first3=Turíbio |last4=Agresta |first4=Marisa Cury |last5=Lotufo |first5=Renato Fraga M. |last6=Kater |first6=Claudio E. |date=December 2006 |title=Divergent responses of serum testosterone and cortisol in athlete men after a marathon race |journal=Arquivos Brasileiros de Endocrinologia & Metabologia |volume=50 |issue=6 |pages=1082–1087 |doi=10.1590/S0004-27302006000600015 |issn=0004-2730 |pmid=17221115 |doi-access=free}}</ref>  Low testosterone is thought to be a physiological adaptation to the sport, as excess muscle caused may be shed through lower testosterone, yielding a more efficient runner. Veteran, lifelong endurance athletes have been found to have more heart scarring than control groups, but replication studies and larger studies should be done to firmly establish the link, which may or may not be causal.<ref>{{Cite journal |last1=Wilson |first1=Mathew G. |last2=O'Hanlon |first2=Rory |last3=Prasad |first3=Sanjay |last4=Deighan |first4=Amanda |last5=MacMillan |first5=Philip |last6=Oxborough |first6=David |last7=Godfrey |first7=Richard J. |last8=Smith |first8=Gill |last9=Maceira |first9=Alicia |date=17 February 2011 |title=Diverse patterns of myocardial fibrosis in lifelong, veteran endurance athletes |journal=Journal of Applied Physiology |volume=110 |issue=6 |pages=1622–6 |doi=10.1152/japplphysiol.01280.2010 |issn=8750-7587 |pmc=3119133 |pmid=21330616}}</ref> Some studies find that running more than {{convert|20|mi|km|abbr=off|sp=us}} per week yields no lower risk for all-cause mortality than non-runners,<ref>{{Cite web |last=Design |first=ISITE |title=OASIS |url=http://www.abstractsonline.com/Plan/ViewAbstract.aspx?sKey=32617aef-b494-41b8-b2bc-3d49357a8976&cKey=984e0396-f663-4068-bbf3-1dc4023c17e1&mKey=%7BFCDB1C1C-280A-4DF1-95F8-2DAA9AB6A8BE%7D |access-date=14 June 2017 |website=abstractsonline.com}}</ref> although these studies are in conflict with large studies that show longer lifespans for any increase in exercise volume.<ref>{{Cite journal |last1=Wen |first1=Chi Pang |last2=Wai |first2=Jackson Pui Man |last3=Tsai |first3=Min Kuang |last4=Yang |first4=Yi Chen |last5=Cheng |first5=Ting Yuan David |last6=Lee |first6=Meng-Chih |last7=Chan |first7=Hui Ting |last8=Tsao |first8=Chwen Keng |last9=Tsai |first9=Shan Pou |date=1 October 2011 |title=Minimum amount of physical activity for reduced mortality and extended life expectancy: a prospective cohort study |journal=Lancet |volume=378 |issue=9798 |pages=1244–1253 |doi=10.1016/S0140-6736(11)60749-6 |issn=1474-547X |pmid=21846575 |s2cid=9538733}}</ref>

Elite-level long-distance running is associated with a three to seven times higher risk of the knee [[osteoarthritis]] later in life compared to non-runners.<ref name="driban">{{Cite journal |vauthors=Driban JB, Hootman JM, Sitler MR, Harris KP, Cattano NM |date=June 2017 |title=Is Participation in Certain Sports Associated With Knee Osteoarthritis? A Systematic Review |journal=Journal of Athletic Training |volume=52 |issue=6 |pages=497–506 |doi=10.4085/1062-6050-50.2.08 |pmc=5488840 |pmid=25574790}}</ref>

The effectiveness of [[shoe insert]]s has been contested. [[Memory foam]] and similar shoe inserts may be comfortable, but they can make foot muscles weaker in the long term.<ref>{{Cite magazine |last=Richard A. Lovett |author-link=Richard A. Lovett |date=9 June 2014 |title=A Guide to Running Shoe Inserts |url=https://www.runnersworld.com/running-gear/a-guide-to-running-shoe-inserts |magazine=[[Runner's World]] |access-date=14 April 2018}}</ref> Running shoes with special features,<ref>{{Cite news |last=Arnold |first=John |title=Expensive running shoes don't prevent injuries, but comfortable ones might |work=[[The Conversation (website)|The Conversation]] |url=http://theconversation.com/expensive-running-shoes-dont-prevent-injuries-but-comfortable-ones-might-44314 |access-date=14 April 2018}}</ref> or lack thereof in the case of minimalist designs,<ref>{{Cite journal |last=Craig Payne |date=28 January 2017 |title=RCT of traditional running shoes vs minimalist running shoes |url=https://www.runresearchjunkie.com/rct-of-traditional-running-shoes-vs-minimalist-running-shoes/ |journal=The American Journal of Sports Medicine |volume=45 |issue=5 |pages=1162–1170 |doi=10.1177/0363546516682497 |pmid=28129518 |access-date=14 April 2018 |s2cid=25996480}}</ref> do not prevent [[Running injuries|injury]]. Rather, comfortable shoes and standard running styles are safer.<ref>{{Cite web |title=The evidence-based solution for choosing running shoes |url=http://evidencebasedliving.human.cornell.edu/2015/08/11/the-evidence-on-running-shoes/ |access-date=14 April 2018 |website=evidencebasedliving.human.cornell.edu}}</ref>