People have a pretty intuitive sense of what is healthy – standing is better than sitting, exercise is great for overall health and getting good sleep is imperative.

However, if exercise in the evening may disrupt our sleep, or make us feel the need to be more sedentary to recover, a key question emerges – what is the best way to balance our 24 hours to optimise our health?

Our research attempted to answer this for risk factors for heart disease, stroke and diabetes. We found the optimal amount of sleep was 8.3 hours, while for light activity and moderate to vigorous activity, it was best to get 2.2 hours each.

Finding the right balance

Current health guidelines recommend you stick to a sensible regime of moderate-to vigorous-intensity physical activity 2.5–5 hours per week.

However mounting evidence now suggests how you spend your day can have meaningful ramifications for your health. In addition to moderate-to vigorous-intensity physical activity, this means the time you spend sitting, standing, doing light physical activity (such as walking around your house or office) and sleeping.

Our research looked at more than 2,000 adults who wore body sensors that could interpret their physical behaviours, for seven days. This gave us a sense of how they spent their average 24 hours.

At the start of the study participants had their waist circumference, blood sugar and insulin sensitivity measured. The body sensor and assessment data was matched and analysed then tested against health risk markers — such as a heart disease and stroke risk score — to create a model.

Using this model, we fed through thousands of permutations of 24 hours and found the ones with the estimated lowest associations with heart disease risk and blood-glucose levels. This created many optimal mixes of sitting, standing, light and moderate intensity activity.

When we looked at waist circumference, blood sugar, insulin sensitivity and a heart disease and stroke risk score, we noted differing optimal time zones. Where those zones mutually overlapped was ascribed the optimal zone for heart disease and diabetes risk.

You’re doing more physical activity than you think

We found light-intensity physical activity (defined as walking less than 100 steps per minute) – such as walking to the water cooler, the bathroom, or strolling casually with friends – had strong associations with glucose control, and especially in people with type 2 diabetes. This light-intensity physical activity is likely accumulated intermittently throughout the day rather than being a purposeful bout of light exercise.

Our experimental evidence shows that interrupting our sitting regularly with light-physical activity (such as taking a 3–5 minute walk every hour) can improve our metabolism, especially so after lunch.

While the moderate-to-vigorous physical activity time might seem a quite high, at more than 2 hours a day, we defined it as more than 100 steps per minute. This equates to a brisk walk.

It should be noted that these findings are preliminary. This is the first study of heart disease and diabetes risk and the “optimal” 24 hours, and the results will need further confirmation with longer prospective studies.

The data is also cross-sectional. This means that the estimates of time use are correlated with the disease risk factors, meaning it’s unclear whether how participants spent their time influences their risk factors or whether those risk factors influence how someone spends their time.

Australia’s adult physical activity guidelines need updating

Australia’s physical activity guidelines currently only recommend exercise intensity and time. A new set of guidelines are being developed to incorporate 24-hour movement. Soon Australians will be able to use these guidelines to examine their 24 hours and understand where they can make improvements.

While our new research can inform the upcoming guidelines, we should keep in mind that the recommendations are like a north star: something to head towards to improve your health. In principle this means reducing sitting time where possible, increasing standing and light-intensity physical activity, increasing more vigorous intensity physical activity, and aiming for a healthy sleep of 7.5–9 hours per night.

Beneficial changes could come in the form of reducing screen time in the evening or opting for an active commute over driving commute, or prioritising an earlier bed time over watching television in the evening.

It’s also important to acknowledge these are recommendations for an able adult. We all have different considerations, and above all, movement should be fun.

Christian Brakenridge, Postdoctoral research fellow at Swinburne University Centre for Urban Transitions, Swinburne University of Technology

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

Oral retinoids are a type of medicine used to treat severe acne. They’re sold under the brand name Roaccutane, among others.

While oral retinoids are very effective, they can have harmful effects if taken during pregnancy. These medicines can cause miscarriages and major congenital abnormalities (harm to unborn babies) including in the brain, heart and face. At least 30% of children exposed to oral retinoids in pregnancy have severe congenital abnormalities.

Neurodevelopmental problems (in learning, reading, social skills, memory and attention) are also common.

Because of these risks, the Australasian College of Dermatologists advises oral retinoids should not be prescribed a month before or during pregnancy under any circumstances. Dermatologists are instructed to make sure a woman isn’t pregnant before starting this treatment, and discuss the risks with women of childbearing age.

But despite this, and warnings on the medicines’ packaging, pregnancies exposed to oral retinoids continue to be reported in Australia and around the world.

In a study published this month, we wanted to find out what proportion of Australian women of reproductive age were taking oral retinoids, and how many of these women were using contraception.

Our results suggest a high proportion of women are not using effective contraception while on these drugs, indicating Australia needs a strategy to reduce the risk oral retinoids pose to unborn babies.

Contraception options

Using birth control to avoid pregnancy during oral retinoid treatment is essential for women who are sexually active. Some contraception methods, however, are more reliable than others.

Long-acting-reversible contraceptives include intrauterine devices (IUDs) inserted into the womb (such as Mirena, Kyleena, or copper devices) and implants under the skin (such as Implanon). These “set and forget” methods are more than 99% effective.

The effectiveness of oral contraceptive pills among “perfect” users (following the directions, with no missed or late pills) is similarly more than 99%. But in typical users, this can fall as low as 91%.

Condoms, when used as the sole method of contraception, have higher failure rates. Their effectiveness can be as low as 82% in typical users.

Oral retinoid use over time

For our study, we analysed medicine dispensing data among women aged 15–44 from Australia’s Pharmaceutical Benefit Scheme (PBS) between 2013 and 2021.

We found the dispensing rate for oral retinoids doubled from one in every 71 women in 2013, to one in every 36 in 2021. The increase occurred across all ages but was most notable in young women.

Most women were not dispensed contraception at the same time they were using the oral retinoids. To be sure we weren’t missing any contraception that was supplied before the oral retinoids, we looked back in the data. For example, for an IUD that lasts five years, we looked back five years before the oral retinoid prescription.

Our analysis showed only one in four women provided oral retinoids were dispensed contraception simultaneously. This was even lower for 15- to 19-year-olds, where only about one in eight women who filled a prescription for oral retinoids were dispensed contraception.

A recent study found 43% of Australian year 10 and 69% of year 12 students are sexually active, so we can’t assume this younger age group largely had no need for contraception.

One limitation of our study is that it may underestimate contraception coverage, because not all contraceptive options are listed on the PBS. Those options not listed include male and female sterilisation, contraceptive rings, condoms, copper IUDs, and certain oral contraceptive pills.

But even if we presume some of the women in our study were using forms of contraception not listed on the PBS, we’re still left with a significant portion without evidence of contraception.

What are the solutions?

Other countries such as the United States and countries in Europe have pregnancy prevention programs for women taking oral retinoids. These programs include contraception requirements, risk acknowledgement forms and regular pregnancy tests. Despite these programs, unintended pregnancies among women using oral retinoids still occur in these countries.

But Australia has no official strategy for preventing pregnancies exposed to oral retinoids. Currently oral retinoids are prescribed by dermatologists, and most contraception is prescribed by GPs. Women therefore need to see two different doctors, which adds costs and burden.

Rather than a single fix, there are likely to be multiple solutions to this problem. Some dermatologists may not feel confident discussing sex or contraception with patients, so educating dermatologists about contraception is important. Education for women is equally important.

A clinical pathway is needed for reproductive-aged women to obtain both oral retinoids and effective contraception. Options may include GPs prescribing both medications, or dermatologists only prescribing oral retinoids when there’s a contraception plan already in place.

Some women may initially not be sexually active, but change their sexual behaviour while taking oral retinoids, so constant reminders and education are likely to be required.

Further, contraception access needs to be improved in Australia. Teenagers and young women in particular face barriers to accessing contraception, including costs, stigma and lack of knowledge.

Many doctors and women are doing the right thing. But every woman should have an effective contraception plan in place well before starting oral retinoids. Only if this happens can we reduce unintended pregnancies among women taking these medicines, and thereby reduce the risk of harm to unborn babies.

Dr Laura Gerhardy from NSW Health contributed to this article.

Antonia Shand, Research Fellow, Obstetrician, University of Sydney and Natasha Nassar, Professor of Paediatric and Perinatal Epidemiology and Chair in Translational Childhood Medicine, University of Sydney

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