We’re nearly two months into 2025, but if you’re struggling to hold onto your New Year’s resolution, stay strong, as University of South Australia research shows that forming a healthy habit can take longer than you expect.

In the first systematic review of its kind, UniSA researchers found that new habits can begin forming within about two months (median of 59–66 days) but can take up to 335 days to establish.

It’s an important finding that could inform health interventions to promote healthy behaviours and prevent chronic disease.

In Australia, chronic disease contributes to a large portion of the disease burden. Many conditions, including type 2 diabetes, heart disease, lung diseases and stroke, can be prevented by changing unhealthy habits or lifestyle factors. 

University of South Australia researcher, Dr Ben Singh, says that contrary to popular belief, healthy habits take far longer than three weeks to lock down.

“Adopting healthy habits is essential for long-term well-being but forming these habits – and breaking unhealthy ones – can be challenging,” Dr Singh says.

“At the beginning of the year, many of us are setting goals and making plans for the months ahead –things like being more active, cutting back on sugar, or making healthier food choices – but while common wisdom suggests that it takes just 21 days to form such habits, these claims are not evidence-based.

“In our research, we’ve found that habit formation starts within around two months, but there is significant variability, with formation times ranging from four days to nearly a year.

“So, it’s important for people who are hoping to make healthier habits not to give up at that mythical three-week mark.”

The study of more than 2600 participants also found that certain factors can influence successful habit formation.

“When trying to establish a new healthy habit, success can be influenced by a range of things including how frequently we undertake the new activity, the timing of the practice, and whether we enjoy it or not,” Dr Singh says.

“If you add a new practice to your morning routine, the data shows that you’re more likely to achieve it. You’re also more likely to stick to a new habit if you enjoy it.

“Planning and intending to complete a new behaviour can also help solidify a new habit, so make sure you continue to make time to include your new healthy habits into your everyday activities. This could be as easy as laying out your gym clothes the night before a morning walk or having a healthy lunch ready to go in the fridge.

“Tailoring habit-building strategies into our day and making plans on how we can achieve them, will put you in a position for success.”

While more research is needed, researchers say that these findings can guide public health initiatives and personalised programs that support sustained and healthy behaviour change.

More time spent sitting, reclining or lying down during the day may increase the risk of cardiovascular disease (CVD) and death, according to a study in JACC, the flagship journal of the American College of Cardiology, and presented at the American Heart Association’s Scientific Sessions 2024.

More than roughly 10-and-a-half hours of sedentary behavior per day was significantly linked with future heart failure (HF) and cardiovascular (CV) death, even among people meeting recommended levels of exercise.

“Our findings support cutting back on sedentary time to reduce cardiovascular risk, with 10.6 hours a day marking a potentially key threshold tied to higher heart failure and cardiovascular mortality,” said Shaan Khurshid, MD, MPH, a cardiologist at the Massachusetts General Hospital and co-senior author of the study. “Too much sitting or lying down can be harmful for heart health, even for those who are active.”

Insufficient exercise is a known risk factor for cardiovascular disease (CVD). Over 150 minutes of moderate-to-vigorous physical activity per week is recommended by current guidelines to promote heart health. However, study experts say exercise is only a small fraction of overall daily activity, and the current guidelines don’t provide specific guidance on sedentary behavior which accounts for a much larger portion of daily activity, despite evidence that it’s directly linked with CVD risk.

This study examined the amount of sedentary time at which CVD risk is greatest and explored how sedentary behavior and physical activity together impact the chances of atrial fibrillation (AF), heart failure (HF), myocardial infarction (MI) and CV mortality.

Among the 89,530 study participants of the UK biobank, the average age was 62 years and 56.4% were women. Participants submitted data from a wrist-worn triaxial accelerometer that captured movement over seven days. The average sedentary time per day was 9.4 hours.

After an average follow-up of eight years, 3,638 individuals (4.9%) developed incident AF, 1,854 (2.1%) developed incident HF, 1,610 (1.84%) developed indecent MI and 846 (0.94%) died of CV causes, respectively.

The effects of sedentary time varied by outcome. For AF and MI, the risk increased steadily over time without major shifts. For HF and CV mortality, increase in risk was minimal until sedentary time exceeded about 10.6 hours a day, at which point risk rose significantly, showing a “threshold” effect for the behavior.

For study participants who met the recommended 150 minutes of moderate-to-vigorous physical activity or more, the effects of sedentary behavior on AF and MI risks were substantially reduced, but effects on higher risk of HF and CV mortality remained prominent.

“Future guidelines and public health efforts should stress the importance of cutting down on sedentary time,” Khurshid said. “Avoiding more than 10.6 hours per day may be a realistic minimal target for better heart health.”

In an accompanying editorial comment, Charles Eaton, MD, MS, Director of the Brown University Department of Family Medicine, said the use of wearable accelerometers has shown that exercise is significantly over-estimated by self-report and sedentary behavior is under-estimated.

Eaton said that replacing just 30 minutes of excessive sitting time each day with any type of physical activity can lower heart health risks. Adding moderate-to-vigorous activity cut the risk of HF by 15% and CV mortality by 10%, and even light activity made a difference by reducing HF risk by 6% and CV mortality by 9%.

“This study adds to the growing evidence of a strong link between sedentary behavior and cardiovascular health,” said Harlan M. Krumholz, MD, SM, Harold H. Hines Jr. Professor at Yale School of Medicine and Editor-in-Chief of JACC. “The findings strongly suggest that we need to get people moving to promote better health.”

Running, cycling, or swimming – if you regularly exercise, you’re on track for a long and healthy life.

This is according to a study – “Cardiorespiratory fitness is a strong and consistent predictor of morbidity and mortality among adults: an overview of meta-analyses representing over 20.9 million observations from 199 unique cohort studies” – that was published in the British Journal of Sports Medicine.

The study comprised of 26 systematic reviews with meta-analysis representing more than 20.9 million observations from 199 unique cohort studies. It is the first study to collate all the scientific evidence that looked at the prospective link between cardiorespiratory fitness and health outcomes among adults.

The study found that:

• for every 1-MET increase in cardiorespiratory fitness – the amount of energy used for quiet sitting – a person can reduce their risk of death by 11-17%, and specifically, their risk of heart disease by 18%.
• an increased cardio fitness level will reduce your risk of death from any cause by 11-17%.

Senior author Grant Tomkinson said that cardiorespiratory fitness is probably the most important type of fitness for good health. “Cardiorespiratory fitness (or CRF) is your ability to perform physical activity for a long period of time like running, cycling, and swimming. And in this study, we found prolonged cardiorespiratory fitness is strongly and consistently associated with all types of premature death and incident disease – spanning heart failure, depression, diabetes, dementia and even cancer.”

Tomkinson added that the researchers “summarized the evidence linking CRF to numerous health outcomes and found that those with low levels of CRF are far more likely to die early or develop chronic conditions like heart disease later in life.” Specifically, “we found that every 1-MET increase in CRF, which is the amount of energy used when sitting quietly, reduced the risk of early death from any cause and heart failure by 11–17% and 18%, respectively. For most people, a 1-MET increase in CRF can be achieved through a regular aerobic exercise program.”

For Tomkinson, the message is quite simple: if you do a lot of “huff and puff” exercise, then your risk of dying early or developing diseases in the future is reduced. If you avoid exercise your health may suffer.

Chronic health conditions are an ongoing cause of poor health, disability, and premature death. In Australia, an estimated 11.6 million people (47%) have a chronic and debilitating health conditions, which contributes to two thirds of the burden of disease.

“Clearly, cardiorespiratory fitness is as an important factor for good health. If you are already exercising, this is good news; but if you know you need to up your fitness and movement, then this is a timely reminder,” co-author Dr Justin Lang said.

People can make meaningful improvements through additional moderate physical activity, such as brisk walking at least 150 minutes a week, or kayaking (which means grabbing the Best Folding Kayak).

“And as they improve their fitness, their risk of death and disease will decline. But the onus for improvement should not just sit with the individual, it should also be routinely assessed in clinical and public health practice, so that we can support people to improve their health outcomes,” Lang said.

Through regular assessment, clinicians and exercise professionals could better identify adults at greater risk of early death and initiate exercise programs aimed at increasing CRF through regular physical activity.