Brain Fog and Fatigue in POTS – Hope on the horizon?

POTS is a hugely debilitating condition which is characterised by an abnormally high heart rate when the patient adopts an upright posture. A lot of medical research has focused on trying to reduce the heart rate and this does seem to make a beneficial difference in patients with POTS. However virtually every POTS patient that I have looked after will complain of lots of other symptoms which are not related to an upright posture. These include lack of refreshing sleep, extreme fatigue, gut issues and temperature dysregulation. However one symptom that seems to bother patients the most is a symptom called ‘brain fog’ or mental clouding. These include diminished attention, difficult processing mental tasks and also reduced concentration. This mental fatigue Is often accompanied with severe physical fatigue. Whilst for many patients, the traditional meds seem to help, few of the commonly available treatments do much for the brain fog. 

In my own experience, whenever I have asked any of the experts about brain fog, the answer I get is if you can generally improve their POTS, their brain fog will get better. Another thing i have found to be useful is to give patients intravenous saline and often patients have turned and said that they have felt like a veil has been lifted off. The problems with IV saline however are two-fold – Firstly, the effects don’t last more than a day or two and secondly it does not offer a practical long term solution. 

In terms of other available medications, the medications which can help mental alertness are mostly stimulants. The main concern that doctors have using stimulants is that they could increase the heart rate and make things worse. This is where an interesting medication called Modafinil comes in.

Modafinil is an FDA approved medication which is used for excessive daytime sleepiness in patients with obstructive sleep apnoea. It has also been shown to improve cognitive function and mood problems in patients with Narcolepsy. In addition, there is some evidence that it improves symptoms of depression, anxiety and irritability in patients with sleep apnoea. It does this by increasing levels of serotonin and glutamate the brain. The really interesting thing is that in 2014, a group of researchers decided to study this agent in a small group of patients with POTS (Kpayaeh et al, 2014) and found that Modafinil at a dose of 100mg did not substantially increase the heart rate or make symptoms worse in patients with POTS which therefore suggested that it could be used in this group of patients. In 2010, there was an interesting paper by a very distinguished researcher called Blair Grubb in Toledo which was published in the American Journal of Therapeutics (Kanjwal et al, 2010) where they reported that 40 out of 60 patients with POTS/ orthostatic intolerance reported an improvement in fatigue with Modafinil at a dose of 100-200mg daily. What was interesting was that in 4 patients the fatigue came back after 3 month but in the remaining 36 patients, the improvement in fatigue was maintained beyond 6 months from starting treatment.

There is now an interesting ongoing research study in University of Calgary which aims to study whether the use of Modafinil could make a difference to the millions of patients worldwide who are suffering with mental and physical fatigue from POTS. If any of you are in the area, it may be worth considering participating in this research study.

I hope you found this useful. I would love to receive your comments and remarks

Here is a video i have done on this subject

About the Author:

I'm Dr Sanjay Gupta, a Consultant Cardiologist with specialist interest in Cardiac Imaging at York Teaching Hospital in York, UK. I believe that high quality reliable jargon-free information about health should be available at no cost to everyone in the world.


  1. Lisa Bondurant 3rd June 2021 at 12:31 am - Reply

    Thank you for all your great and thoughtful information about POTS! Your videos are always so helpful and informative in dealing with this awful illness that few doctors understand. Brain fog is one of the most debilitating symptoms that effects my 2 children with POTS.

  2. Matt 19th June 2021 at 10:20 pm - Reply

    Thanks for the info on hiatus hernia and breathing difficulties/AF. My cardiologiist is looking at exactly this for me after mis diagnoses over the last 2.5 years by other specialists.

    As for modafinil and POTS I think researchers do not fully understand modafinil and its side effects. Subjectively a lot of sleep disorder patients on modafinil report mood swings, headaches and anxiety taking the drug and often end up switching over to methylphenidate or the like which seems to have less side effects. Also modafinil is the choice of starter drug for sleep doctors, but not patients but choice is limited in that regard. (I manage some sleep disorder chat groups so talk to other patients regularly.)

    If you want to know more about the drug talk to Paul Reading up at James Cook.

  3. Victoria 8th July 2021 at 10:08 pm - Reply

    I have just been diagnosed with POTS after 15 months of terrible symptoms and no diagnosis. Your information and videos are an absolute blessing. Thank you for your kind generosity.

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