If you find yourself struggling to log even 20 minutes of jogging each day, it could be due to dopamine levels in your brain. 

According to research published in the Journal of Neuroscience, dopamine levels in three specific areas of the brain were able to predict if a person was highly motivated or not, but not in the way previously thought.  

Test subjects who were willing to work hard for higher rewards had a higher release of dopamine in the striatum and ventromedial areas of the brain - areas known to impact reward and motivation. Conversely, test subjects who were less willing to undergo hard tasks had high levels of dopamine in the anterior insula region of the brain, disproving the long-held belief that dopamine affects all areas of the brain in the same way.   

The fact that dopamine can have a negative effect on motivation came as a surprise to researchers and means that scientists will have to re-examine the use of psychotropic medications that affect dopamine levels in patients with depression, ADHD and depression.