Made from fermented apples and naturally high in acetic acid, apple cider vinegar has been popular in recent years for its purported health benefits – from antibacterial properties to antioxidant effects and potential for helping manage blood sugars.

Its origins as a health tonic stretch much further back. Hippocrates used it to treat wounds, fever and skin sores.

An experimental study, released today, looks into whether apple cider vinegar could be effective for weight loss, reduce blood glucose levels and reduce blood lipids (cholesterol and triglycerides).

The results suggest it could reduce all three – but it might not be as simple as downing an apple cider vinegar drink a day.

What did they do?

A group of scientists in Lebanon did a double-blinded, randomised, clinical trial in a group of overweight and obese young people aged from 12–25 years.

Researchers randomly placed 30 participants in one of four groups. The participants were instructed to consume either 5, 10 or 15ml of apple cider vinegar diluted into 250ml of water each morning before they ate anything for 12 weeks. A control group consumed an inactive drink (a placebo) made (from lactic acid added to water) to look and taste the same.

Typically this sort of study provides high quality evidence as it can show cause and effect – that is the intervention (apple cider vinegar in this case) leads to a certain outcome. The study was also double-blinded, which means neither the participants or the scientists involved with collecting the data knew who was in which group.

So, what did they find?

After a period of three months apple cider vinegar consumption was linked with significant falls in body weight and body mass index (BMI). On average, those who drank apple cider vinegar during that period lost 6–8kg in weight and reduced their BMI by 2.7–3 points, depending on the dose. They also showed significant decreases in the waist and hip circumference.

The authors also report significant decreases in levels of blood glucose, triglycerides, and cholesterol in the apple cider groups. This finding echoes previous studies. The placebo group, who were given water with lactic acid, had much smaller decreases in weight and BMI. There were also no significant decreases in blood glucose and blood lipids.

From animal studies, it is thought the acetic acid in apple cider vinegar may affect the expression of genes involved in burning fats for energy. The new study did not explore whether this mechanism was involved in any weight loss.

Is this good news?

While the study appears promising, there are also reasons for caution.

Firstly, study participants were aged from 12 to 25, so we can’t say whether the results could apply to everyone.

The statistical methods used in the study don’t allow us to confidently say the same amount of weight loss would occur again if the study was done again.

And while the researchers kept records of the participants’ diet and exercise during the study, these were not published in the paper. This makes it difficult to determine if diet or exercise may have had an impact. We don’t know whether participants changed the amount they ate or the types of food they ate, or whether they changed their exercise levels.

The study used a placebo which they tried to make identical in appearance and taste to the active treatment. But people may still be able to determine differences. Researchers may ask participants at the end of a study to guess which group they were in to test the integrity of the placebo. Unfortunately this was not done in this study, so we can’t be certain if the participants knew or not.

Finally, the authors do not report whether anyone dropped out of the study. This could be important and influence results if people who did not lose weight quit due to lack of motivation.

Any other concerns?

Apple cider vinegar is acidic and there are concerns it may erode tooth enamel. This can be a problem with any acidic beverages, including fizzy drinks, lemon water and orange juice.

To minimise the risk of acid erosion some dentists recommend the following after drinking acidic drinks:

• rinsing out your mouth with tap water afterwards
• chewing sugar-free gum afterwards to stimulate saliva production
• avoiding brushing your teeth immediately after drinking because it might damage the teeth’s softened top layer
• drink with a straw to minimise contact with the teeth.

Down the hatch?

This study provides us with some evidence of a link between apple cider vinegar and weight loss. But before health professionals can recommend this as a weight loss strategy we need bigger and better conducted studies across a wider age range.

Such research would need to be done alongside a controlled background diet and exercise across all the participants. This would provide more robust evidence that apple cider vinegar could be a useful aid for weight loss.

Still, if you don’t mind the taste of apple cider vinegar then you could try drinking some for weight loss, alongside a healthy balanced and varied dietary intake. This study does not suggest people can eat whatever they like and drink apple cider vinegar as a way to control weight.

Evangeline Mantzioris, Program Director of Nutrition and Food Sciences, Accredited Practising Dietitian, University of South Australia

This article is republished from The Conversation under a Creative Commons license. Read the original article.

You’ve had a cold or the flu and your symptoms have begun to subside. Your nose has stopped dripping, your cough is clearing and your head and muscles no longer ache.

You’re ready to get off the couch. But is it too early to go for a run? Here’s what to consider when getting back to exercising after illness.

Exercise can boost your immune system – but not always

Exercise reduces the chance of getting respiratory infections by increasing your immune function and the ability to fight off viruses.

However, an acute bout of endurance exercise may temporarily increase your susceptibility to upper respiratory infections, such as colds and the flu, via the short-term suppression of your immune system. This is known as the “open window” theory.

A study from 2010 examined changes in trained cyclists’ immune systems up to eight hours after two-hour high-intensity cycling. It found important immune functions were suppressed, resulting in an increased rate of upper respiratory infections after the intense endurance exercise.

So, we have to be more careful after performing harder exercises than normal.

Can you exercise when you’re sick?

This depends on the severity of your symptoms and the intensity of exercise.

Mild to moderate exercise (reducing the intensity and length of workout) may be OK if your symptoms are a runny nose, nasal congestion, sneezing and minor sore throat, without a fever.

Exercise may help you feel better by opening your nasal passages and temporarily relieving nasal congestion.

However, if you try to exercise at your normal intensity when you are sick, you risk injury or more serious illness. So it’s important to listen to your body.

If your symptoms include chest congestion, a cough, upset stomach, fever, fatigue or widespread muscle aches, avoid exercising. Exercising when you have these symptoms may worsen the symptoms and prolong the recovery time.

If you’ve had the flu or another respiratory illness that caused a high fever, make sure your temperature is back to normal before getting back to exercise. Exercising raises your body temperature, so if you already have a fever, your temperature will become high quicker, which makes you sicker.

If you have COVID or other contagious illnesses, stay at home, rest and isolate yourself from others.

When you’re sick and feel weak, don’t force yourself to exercise. Focus instead on getting plenty of rest. This may actually shorten the time it takes to recover and resume your normal workout routine.

I’ve been sick for a few weeks. What has happened to my strength and fitness?

You may think taking two weeks off from training is disastrous, and worry you’ll lose the gains you’ve made in your previous workouts. But it could be just what the body needs.

It’s true that almost all training benefits are reversible to some degree. This means the physical fitness that you have built up over time can be lost without regular exercise.

To study the effects of de-training on our body functions, researchers have undertaken “bed rest” studies, where healthy volunteers spend up to 70 days in bed. They found that V̇O₂max (the maximum amount of oxygen a person can use during maximal exercise, which is a measure of aerobic fitness) declines 0.3–0.4% a day. And the higher pre-bed-rest V̇O₂max levels, the larger the declines.

In terms of skeletal muscles, upper thigh muscles become smaller by 2% after five days of bed rest, 5% at 14 days, and 12% at 35 days of bed rest.

Muscle strength declines more than muscle mass: knee extensor muscle strength gets weaker by 8% at five days, 12% at 14 days and more than 20% after around 35 days of bed rest.

This is why it feels harder to do the same exercises after resting for even five days.

But in bed rest studies, physical activities are strictly limited, and even standing up from a bed is prohibited during the whole length of a study. When we’re sick in bed, we have some physical activities such as sitting on a bed, standing up and walking to the toilet. These activities could reduce the rate of decreases in our physical functions compared with study participants.

How to ease back into exercise

Start with a lower-intensity workout initially, such as going for a walk instead of a run. Your first workout back should be light so you don’t get out of breath. Go low (intensity) and go slow.

Gradually increase the volume and intensity to the previous level. It may take the same number of days or weeks you rested to get back to where you were. If you were absent from an exercise routine for two weeks, for example, it may require two weeks for your fitness to return to the same level.

If you feel exhausted after exercising, take an extra day off before working out again. A day or two off from exercising shouldn’t affect your performance very much.

Ken Nosaka, Professor of Exercise and Sports Science, Edith Cowan University

This article is republished from The Conversation under a Creative Commons license. Read the original article.