How do we know when it is safe to go back to Sport after a Concussion? 

Two Italian research papers written in 2012 give us the best evidence for the timing of a safe return to Sport. (1,2).  

It is well known that after a concussion, the brain has reduced energy levels, often by up to 20%. The brain weighs about 2% of our body weight but uses 15-20% of our blood flow. This is because it needs a lot of energy to perform the complex processing of all the information it receives as well as driving all the functions it performs, even when we are sleeping! 

Measuring these energy stores is very difficult but this group of Italian researchers were able to assess energy levels using a complex and costly measure called Proton Magnetic Resonance Spectroscopy (PMRS). 

A concussion disrupts the important energy stores in our brain. Here are the important points they learned from their research.  

• Eleven athletes, (3 females and 8 males) who had a Sports Related Concussion were tested using the PMRS on Day 3, 15, 30 and 45 after the concussion. They compared the results with 11 healthy matched controls, who did the same testing. The athletes with concussion had reduced energy levels, compared to the non-injured controls at Day 3  and Day 15. At Day 30 they were still less but very minimally, (and not significant), with energy levels back to normal at Day 45. 

 

• Those results were for the athletes who did the proper rehabilitation. However, 6 of the athletes decided to go back to sport before their energy levels were back to normal. “Why did they do that?” you ask…. It was because they felt OK.  

 

Even though energy levels take 30+ days to recover, the athlete’s symptoms settled much quicker,  on average by Day 15,  post injury. As they ‘felt’ ok,  they thought they were ready to go back to sport. (Interestingly all 6 were males – 2 soccer players,3 boxers and a rugby player) 

 

• All 6 of these athletes sustained another concussion, whilst their brain was still low on energy from the first concussion. The results showed that the second time around, they had more symptoms (4-6) compared to the initial injury (2-3) and they took, on average, 41 days for the symptoms to settle. That’s almost three times longer than the single concussion athletes.  

 

• The most telling result was the time for the energy levels to get back to normal for the double concussion athletes. This was 81 days(av) – THREE TIMES LONGER than the athletes who didn’t return to sport 

WHATS THE LESSON TO BE LEARNT? 

1. Feeling good (that is, no symptoms) is not a great measure for return to sport. 
2.  Having a second concussion before your brain has recovered from the first, creates longer term issues and may be the end of your season! 

References 

1. Decrease in N-Acetylaspartate Following Concussion May Be Coupled to Decrease in Creatine Roberto Vagnozzi et al, J Head Trauma Rehabil (2012). 

1. The Importance of Restriction from Physical Activity in the Metabolic Recovery of Concussed Brain, Giuseppe Lazzarino et al, Chap 25, Brain Injury – Pathogenesis, Monitoring, Recovery and Management, (2012).