I mentioned a few weeks ago how researchers have been trying to electrically stimulate the vagus nerve, which is now thought to help treat everything from anxiety to depression.
In this study, researchers from the University of Auckland found that the vagus nerve, plays a significant role during exercise. Contrary to the prevailing understanding that only the ‘fight or flight’ nervous system is active during exercise, this study shows that activity in the vagus nerve actually increases. This helps the heart pump blood more effectively, supporting the body’s increased oxygen needs during exercise.
Interestingly, especially for people I know who have heart failure, they also identified that the vagus nerve releases a peptide which helps dilate coronary vessels. This allows more blood to flow through the heart.
The vagus nerve, known for its role in 'resting and digesting,' has now been found to have an important role in exercise, helping the heart pump blood, which delivers oxygen around the body.Source: Vagus nerve active during exercise, research finds | Medical Xpress
Currently, exercise science holds that the ‘fight or flight’ (sympathetic) nervous system is active during exercise, helping the heart beat harder, and the ‘rest and digest’ (parasympathetic) nervous system is lowered or inactive.
However, University of Auckland physiology Associate Professor Rohit Ramchandra says that this current understanding is based on indirect estimates and a number of assumptions their new study has proven to be wrong. The work is published in the journal Circulation Research.
“Our study finds the activity in these ‘rest and digest’ vagal nerves actually increases during exercise,” Dr. Ramchandra says.
There is a lot of interest in trying to ‘hack’ or improve vagal tone as a means to reduce anxiety. Investigating this was outside the scope of the current study. Dr. Ramchandra says we do know that the vagus mediates the slowing down of heart rate and if we have high vagal activity, then our hearts should beat slower.
“Whether this is the same as relaxation, I am not sure, but we can say that regular exercise can improve vagal activity and has beneficial effects."
If scientists have indeed got this correct, it’s an incredible finding.
Prof Duarte led a seven-month circumnavigation of the globe in the Spanish research vessel Hesperides, with a team of scientists collecting echo-soundings of mesopelagic fish.Source: Ninety-five per cent of world’s fish hide in mesopelagic zone | Phys.org
He says most mesopelagic species tend to feed near the surface at night, and move to deeper layers in the daytime to avoid birds.
They have large eyes to see in the dim light, and also enhanced pressure-sensitivity."
They are able to detect nets from at least five metres and avoid them," he says."
Because the fish are very skilled at avoiding nets, every previous attempt to quantify them in terms of biomass that fishing nets have delivered are very low estimates."
So instead of different nets what we used were acoustics … sonar and echo sounders."
The advice to date has, quite rightly, to get any COVID vaccine that’s available to you. For me, that’s meant a double dose of AstraZeneca, and I’m happy about that.
But as the pandemic progresses, we need to be aware that some vaccines are more effective than others. This working paper, building on one published in Nature earlier this year, looks at how ‘fractional dosing’ of the Moderna and Pfizer vaccines could reach more people more quickly.
Needless to say, we shouldn’t be in the position where people in less developed countries are getting access to vaccines much more slowly than the rest of the world. But, pragmatically speaking, this may help.
We supplement the key figure from Khoury et al.’s paper to show that fractional doses of the Moderna and Pfizer vaccines have neutralizing antibody levels (as measured in the early phase I and phase II trials) that look to be on par with those of many approved vaccines. Indeed, a one-half or one-quarter dose of the Moderna or Pfizer vaccine is predicted to be more effective than the standard dose of some of the other vaccines like the AstraZeneca, J&J or Sinopharm vaccines, assuming the same relationship as in Khoury et al. holds. The point is not that these other vaccines aren’t good–they are great! The point is that by using fractional dosing we could rapidly and safely expand the number of effective doses of the Moderna and Pfizer vaccines.Source: A Half Dose of Moderna is More Effective Than a Full Dose of AstraZeneca | Marginal REVOLUTION
One more point worth mentioning. Dose stretching policies everywhere are especially beneficial for less-developed countries, many of which are at the back of the vaccine queue. If dose-stretching cuts the time to be vaccinated in half, for example, then that may mean cutting the time to be vaccinated from two months to one month in a developed country but cutting it from two years to one year in a country that is currently at the back of the queue.