When do you stop getting benefits from exercise?

From Danielle Baron’s article in International Medical News 10 August 18

As with many different health interventions, there is a sweet spot between doing enough of it and doing too much of it. Too little, and it is not effective. Too much and you could cause unexpected negative repercussions.  The subject of exercise has been investigated regarding its effect on mental health.

Over 1.2 million USA citizens were asked about their exercise habits and their mental wellbeing between 2011 and 2015 by researchers at the Centers for Disease Control and Prevention.

All exercise types improved mental health but popular team sports were particularly effective in boosting mental health. The optimal duration of exercise was between 30 and 60 minutes a session, three to five times a week.

Sessions of longer than 90 minutes or done more than 23 times a month however, were related to WORSE mental health.

The authors conclude that blanket advice on exercise could be improved by being more specific about the types, durations and frequencies that were more likely to improve mental health and that further studies could be helpful.

Chekroud SR et al. Association between physical exercise and mental health in 1.2 million individuals in the USA between 2011 and 2015: a cross sectional study. Lancet Psychiatry. Published online 8 August 2018. doi: 10.1016/S2215-0366(18)30227-X

My comments: Oh dear! Well, I’ve got the duration right at 40 minutes but I hate team sports (because I’m useless at hand to eye or foot coordination) and I aim to exercise every day, which these researchers considered “excessive”.  Maybe the team sports were more beneficial because of the socialisation aspect as well as the physical aspect. Maybe less than 23 times a month made it something to look forward to and a dopamine hit , “I’ve achieved that” rather than a black mark ” I failed to do my exercise session”   as I tend to think about it. I can see the downsides of exercise addiction reflected in this piece of research. 

High dose Vitamin D improves cardiovascular health markers

Adapted from UK Medical News 17 July 2018

Several different health measures, all which improve your cardiovascular outcomes, have been found to result from high dose vitamin D supplementation. You are likely to need to take at least 4,000 iu a day though, depending on how much extra sunshine you are exposed to regularly.

A meta-analysis of 81 randomised controlled trials looked at almost one thousand patients randomised to taking supplements or to a control group who did not. The active and control groups were both roughly 5,000 each.  The durations of the trials varied but averaged out at ten months. The doses ranged from 400 iu a day to 12,000 iu a day. The average taken was 3,000 iu a day.

The outcomes were related to the blood level of vitamin D achieved. Levels had to be over 86 nmol/L to get benefits. You need to take over 4,000 iu a day to get vitamin D concentrations of 100 nmol/L or more.  My comment:This does mean that the minimum levels advised by the Scottish Chief Medical Officer last year are way too low to see the benefits discussed here.

So what extra benefits do you see?

lower systolic and diastolic blood pressure.

lower high sensitivity C reactive protein.

lower serum parathyroid hormone.

lower triglycerides.

lower total cholesterol.

lower low density lipoprotein.

high density lipoprotein increased.

All benefits were numerically small but did reach statistical significance. Cardiovascular outcomes were not measured directly, only blood markers and blood pressure.

Mirhosseini N et al. Vitamin D Supplementation. Serum 25(OH)D Concentrations and cardiovascular disease risk factors: A systematic review and meta-analysis. Front Cardiovasc Med. 2018 July 12.

 

 

 

 

Metformin improves blood sugar and vascular health in type one children

 From Diabetes in Control: Metformin Improves Vascular Health in Children With Type 1 Diabetes
Nov 18, 2017
In individuals with type 1 diabetes (T1DM), cardiovascular disease (CVD) is a major issue and the primary cause of death.

Vascular changes can be detected years before progression to CVD. Targeting blood sugar regulation early in patients at high risk of developing T1DM and in those already diagnosed with T1DM, could potentially help reduce vascular dysfunction risk and even reverse changes already made in vascular function.

Past studies have shown that in adults with T1DM, metformin reduces HbA1c, BMI, and required insulin doses. It has also been suggested that metformin leads to reduced cardiovascular events and better blood sugar regulation in patients with type 2 diabetes. Studies conducted on children with T1DM suggest the same benefits. However, there is currently no research on how metformin affects vascular function in children with T1DM.
A double blind, randomized, placebo-controlled trial was conducted to evaluate the association between metformin and vascular health in children with T1DM over a 12-month period. The study included a total of 90 children from a Women’s and Children’s Hospital in South Australia.  Children were randomly divided into two groups to receive either the metformin intervention or the placebo intervention. Children who weighed 60kg or greater received 1gm of metformin twice daily and those who weighed less than 60kg received 500mg twice daily. Doses were then increased to the complete dose over a period of 2 to 6 weeks.
Follow-up was conducted at 3, 6, and 12 months from the start of the study. Vascular function was obtained at baseline and at every follow-up visit using the brachial artery ultrasound, HbA1C, insulin dose, and BMI were among some of the other outcomes measured.
Results show that vascular function defined by GTN improved over the 12-month period by 3.3% in the metformin intervention group regardless of HbA1c when compared to the placebo group (95% CI 0.3 to 6.3; P=0.03). GTN was found to be the highest in the metformin group at 3 months when compared to placebo. Children in the metformin group also experienced significant improvement (P=0.001) in HbA1c levels at 3 months (8.4%; 95% CI 8.0 to 8.8) (68mmol/mol; 95% CI 64 to 73) when compared to the placebo group (9.3%; 95% CI 9.0 to 9.7). At 12 months, the overall difference between HbA1c improvement between the two groups was lower but remained a significant 1.0% (95% CI 0.4 to 1.5) 10.9mmol/mol (95% CI 4.4 to 16.4), P=0.001. In addition, it was found that children in the metformin group had a decreased insulin dose requirement of 0.2 units/kg/day throughout the 12-month period compared to those in the placebo group (95% CI 0.1 to 0.3, P=0.001).
The following study determined that children with T1DM with above average BMIs and taking metformin saw a significant improvement in vascular smooth muscle function compared to those not taking metformin. The study suggested that in addition to vascular health, metformin also improved HbA1c levels and reduced total daily insulin dose. It was found that improvements in both vascular function and HbA1c were the highest at 3 months. This is most likely due to medication adherence being the highest around 3 months.
Practice Pearls:
In children with above average weight and who were diagnosed with type 1 diabetes, metformin provides a significant improvement in vascular smooth muscle function.
Metformin provides a significant improvement in HbA1c levels in children with type 1 diabetes.
In addition to vascular health and HbA1c benefits, metformin further aids in reducing daily insulin dose in children with type 1 diabetes.
Reference:
Anderson JJA, Couper JJ, Giles LC, et al. Effect of Metformin on vascular function in children with type 1 diabetes: A 12 month randomized controlled trial. 2017. J Clin Endocrinol Metab. 2017; 0: 1-16.

Vegetable oil ingestion not so sunny after all

Adapted from BMJ 9 Feb 13 Use of dietary linoleic acid for secondary prevention  of coronary heart disease and death: evaluation of recovered data from the Sydney Diet Heart Study and updated meta-analysis. Christopher E Ramsden et al

Despite lack of evidence to the contrary I still see NHS dieticians telling patients to avoid naturally occurring saturated fat such as butter, cream and the fat in animal meats. This study didn’t get much publicity at the time so here it is again.

The question was, does increasing dietary omega 6 linoleic acid in the place of saturated fat reduce the risk of death from coronary heart disease?

What happened was that in the Sydney Diet Heart Study, a RCT done between 1966 and 1973, saturated fat (thought to produce heart attacks) was replaced by omega 6 fatty acids from Safflower oil ( vegetable oil and margarines, thought to be heart healthy). Although the blood cholesterol levels decreased in the intervention group, deaths from all causes, coronary heart disease and cardiovascular disease, all increased.

The subjects were all men aged 30-59 who had had a recent heart attack.  As an example, all cause mortality was 17.2% in the intervention group compared to 11.8% in the control group. Results for cardiovascular disease were similar.

It is mystifying that dietary advice telling people to swap lard for vegetable oils and butter for margarine is still going on. Very telling is that date that this study was done. The results would have been out by 1975.

Obesity makes asthma particularly difficult to control

From British Thoracic Society Winter Scientific Meeting December 2017 London

Researchers have demonstrated that diet induced obesity leads to the development of airways hyper-reactivity through the interplay of an immunological and metabolic pathway.

Resultant asthma can affect children as well as adults. Unfortunately obesity associated asthma responds poorly to standard asthma medications including steroids and can result in more hospitalisation and a reduced quality of life.

The most effective obesity treatment is probably bariatric surgery to achieve sustained weight loss. In contrast dietary management and drugs are far less effective.

Polycystic ovary syndrome is linked to autism in offspring

Cambridge University Autism Research Centre has found that compared to women who do not have polycystic ovary syndrome, women who do have this have about double the risk of having a child with autism.  The risk was slightly higher in male children compared to female children.

Cherskov A et al. Polycystic ovary syndrome and autism: At test of the prenatal sex steroid theory. Transl Psychiatry. Aug 1 2018. doi:10.1038/s41398-018-01867.

The UK and US are the only western countries where life expectancy is falling

Researchers looked at 17 high income countries to evaluate trends in national mortality.

In the UK there has been a drop of a few months in life expectancy for both men and women over the age of 65. Degenerative diseases were the main cause such as respiratory disease, circulatory disease, Alzheimer’s disease, nervous system disease and mental disorders.

In the USA drug overdoses were responsible for the decline in life expectancy.

The study looked at mortality between 2014 and 2015. A sixty five year old in the UK at that time would have been born in 1950, after the start of the NHS.

We will need to wait to see if this trend will reverse or not.

British Medical Journal. UK life expectancy drops while other western countries improve. National Health Services. 2018 August 16.