Q: I sustained a “mild” concussion about a month ago and seem to be doing well. I am planning to begin work at 3100 m (10,200 feet) starting at the end of the month. Should I be concerned? I have worked at this altitude before without any problems.
I do not believe that you should have a particular concern regarding work at altitude because of the recent concussion per se.
Also frequently referred to as a traumatic brain injury (TBI), a concussion is commonly diagnosed clinically when a person experiences any loss of consciousness, confusion, or amnesia following a blow to the head. Increased intracranial pressure (increased ICP) or brain swelling is the anticipated problem or what we worry about afterward. The swelling results from bleeding or the accumulation of edema (fluid) in brain tissue. The early symptoms of increased ICP include persistent vomiting, worsening headache and deterioration of one’s mental state. It does not sound like you had these symptoms or have this problem now.
Do you have any other symptoms now? Frequently, following a blow to the head, even without ever experiencing a concussion, people can develop a post concussive syndrome (PCS). The symptoms of PCS include headache, insomnia, feeling more tired than usual, blurry vision, light sensitivity, difficulty concentrating, feeling off balance, and emotional liability. These are not signs of increased ICP; they can last for weeks. If you have any of these, they could get worse at altitude and thereby potentially make you more accident prone.
People who go to altitude, especially over 3000 m (9800 ft), are at risk to develop altitude-related increased ICP called high altitude cerebral edema (HACE). This is related to the lower oxygen levels and in part, to the resulting reflex increase in brain perfusion or blood flow. Theoretically, I suppose, if you were continuing to have a slow blood leak from your injury, it could increase in size more quickly as a result of going to 3100 m. But without ICP symptoms now, this seems very unlikely…unless you sustain another TBI.
I do not know whether a TBI with or without PCS makes one more susceptible to HACE. I doubt it but I could find no substantive references one way or the other.
If you are feeling fine, go for it and have a great time. Remember, the best way to minimize altitude symptoms is to ascent gradually, especially over 2500 m (8200 ft). In addition, increase your physically activity as you acclimate to the new environment. Some good rules include:
1. If you can, before sleeping above 3000 m, spend a night above 1500 m (5000 ft).
2. Above 3000 m, don’t sleep higher than 300 – 500 m (1000 to 1650 ft) above your previous night’s sleeping altitude.
3. With each 1000 m (3300 ft) in altitude gain, add a rest day and/or sleep at the same altitude for 2 consecutive nights.
If you want more information on altitude, check out The International Society of Mountain Medicine. They have a nice summary.