I’ve always struggled with inconsistent sleep, staying up late and waking up at different times each day. My love for coffee was also on an all-time high with trying all the season specials. But it is only recently, I learned how this irregular sleep pattern and caffeine could increase my risk of heart attack and stroke. Now, I’m prioritizing a consistent sleep schedule and cutting out caffeine after 3 PM to protect my heart.

A new, shocking study shows that irregular sleep patterns can greatly increase the risk of heart attack and stroke. But that's not all: the timing of your caffeine intake could also play a critical role in your cardiovascular health. If you are struggling with inconsistent sleep patterns and regularly sipping on caffeinated beverages late in the day, you may be unknowingly putting yourself at risk for serious heart-related issues.

For most people, sleep is something of a given and we often only consider ourselves as long as we get our required seven to nine hours. However, according to a recent study conducted by researchers at the Children's Hospital of Eastern Ontario, it may not be that long after all. The study, which included more than 72,000 participants, found that people with irregular sleep patterns—those who fall asleep and wake up at vastly different times each day—face a 26% higher risk of experiencing a heart attack or stroke. This increased risk persisted even for those who managed to get enough sleep. The study followed up participants for eight years to track heart events such as heart attacks, strokes, and heart failure. The conclusions were clear: irregular sleep, even if it's sufficient in duration, is a major cardiovascular risk factor.

The researchers found that those whose sleep patterns were highly irregular had a significantly greater chance of life-threatening heart issues. The more erratic your sleep schedule, the greater the risk, regardless of how many hours you sleep. In fact, people with irregular sleep schedules showed worse cardiovascular health outcomes, including higher rates of high blood pressure, elevated stress hormones, and poor blood sugar and cholesterol management.

Senior scientist Dr. Jean-Philippe Chaput said "sleep regularity may be more relevant than sufficient sleep duration in modulating MACE [major adverse cardiovascular event] risk." In the study, it shows that our bodies are comfortable with consistency, and a varied sleep schedule may interfere with other processes that keep us healthy, especially the heart.

Is it Caffeine After 3 PM Causing Sleeplessness?

Another daily habit that may be putting your heart at risk is caffeine consumption after 3 PM. According to Dr. Chaput, the experts emphasize the need for a healthy sleep schedule and avoiding caffeine late in the day. Caffeine can stay in your blood for up to eight hours, and its consumption later in the afternoon can disrupt your sleep cycle.

Consistent, good-quality sleep is necessary for maintaining healthy cardiovascular function, and the disruption of this by late-day caffeine intake exacerbates the risks posed by irregular sleep. When you drink coffee, tea, or other caffeinated beverages too late, the stimulant effect on your nervous system makes it harder to fall asleep at a regular time. This can lead to inconsistent sleep patterns, which, as we have seen, can be harmful to heart health.

Dr Chaput insists that humans need to adopt practices that contribute to regularized sleep habits. This can be attained by establishing a proper sleeping and waking schedule, eliminating afternoon intake of stimulants such as caffeine, and making your body clock coincide with the lifestyle one leads.

How Does Poor Sleep Affect Heart Health?

According to the experts, the disturbance due to irregular sleep patterns impacts more than one physiological process involved in the maintenance of the healthy heart. For example, poor sleep can be associated with increased inflammation of the body, weakened immunity, and altered regulation of blood sugar and cholesterol, all of which contribute to increased blood pressure and weakening endothelial function, both associated with an increased risk for cardiovascular diseases. Sleep also plays a very important role in regulating stress hormones. Poor or disturbed sleep results in increased levels of cortisol, the stress hormone, which increases blood pressure and can have negative impacts on cardiovascular health over time.

Scientists hypothesize that these disturbances trigger a series of negative effects that enhance the risk of developing chronic heart conditions, including hypertension, atherosclerosis, or even heart failure.

Tips to Protect Your Heart and Improve Your Sleep

In order to protect your heart, experts recommend several proactive measures to improve your sleep patterns and lifestyle. First, maintain a regular sleep schedule whereby you go to bed and wake up at the same time every day, including weekends. Consistency will keep your body's internal clock in check.

Along with regulating your sleep, paying attention to your caffeine habits is just as important. To reduce your risk of heart disease and stroke, experts suggest avoiding caffeine after 3 PM. If you’re sensitive to caffeine, this rule becomes even more critical.

In addition, the introduction of stress-reducing activities like yoga or mindfulness can also be beneficial to lower cortisol levels, and therefore both sleep and heart health can improve. A diet rich in antioxidants, healthy fats, and low on processed sugars also helps maintain cholesterol levels and reduce inflammation.

Does Your Sleep Environment Also Has A Role To Play

Apart from the timing of caffeine and your sleep schedule, another very overlooked factor is the quality of your sleep environment. Scientists have long known that the environment in which you sleep has a huge impact on the quality of your rest. Poor quality of sleep, even if your sleep schedule is regular, can cause health risks that are very much the same as those that arise from irregular sleep patterns.

Here’s an additional tip: make sure your bedroom is conducive to restful sleep. This means keeping your room dark, quiet, and cool. A temperature of around 65°F (18°C) is ideal for most people. Consider investing in a comfortable mattress and pillows, and avoid screen time at least 30 minutes before bed to allow your brain to unwind.

Irregular sleep, in association with taking caffeine in late parts of the day, can risk heart attack and stroke, but a simple maintenance of a sleep schedule, the reduction of consumption of afternoon caffeine, and sleep environmental awareness can definitely safeguard one's heart along with total health.

Your sleep is more than just a time for rest; it's a vital component of your long-term health, and maintaining consistency in your sleep habits is one of the best things you can do for your heart.

Climate change and rapid urbanization are changing mosquito habitats, and shifting dengue serotypes are reshaping the disease landscape in India. As a result, the country is now witnessing a transformation in how dengue spreads, who it affects, and how severe infections can become.

Once considered a seasonal monsoon illness, dengue is now increasingly becoming a year-round public health challenge, extending into hill states, semi-urban regions, and previously low-risk geographies.

In an exclusive interview with HealthandMe, Dr. Shikha Taneja Malik, Senior Scientific Affairs Manager, Drugs for Neglected Diseases initiative (DNDi), South Asia, discussed why India’s dengue numbers are likely being massively undercounted, how surveillance and diagnostic gaps are masking the real scale of the crisis, and why young adults are facing more severe infections due to changing serotypes.

Dr. Shikha also explained the urgent global push for affordable therapeutics and the challenges India still faces in developing an indigenous dengue vaccine despite its strong manufacturing capacity.

Here are the excerpts from the interview:

Q. Dengue was always called a monsoon disease. Is that label now dangerously misleading?

Dr. Shikha: Yes, I would argue that labels are not just outdated but risky, too. What we are seeing across India and across the region is a fundamental shift in the transmission pattern.

Dengue used to follow a fairly predictable seasonal curve — cases would spike between July and November, track the monsoon, and then recede. That curve is flattening. We are now seeing cases in February, March, and May — months that were previously considered safe. Delhi, Mumbai, Bengaluru — cities that used to have clear off-seasons for dengue — are reporting year-round transmission.

Warmer temperatures, altered rainfall patterns, unplanned urbanization, and poor sanitation have lengthened transmission seasons, making dengue a year-round systemic crisis. Models now predict year-round transmission in coastal regions, though monsoon months will retain the highest peak.

Also read: National Dengue Day 2026: India Reports 6,927 Cases And 10 Deaths In 2026

Q. Are serotype shifts driving changing dengue patterns, especially in young adults?

Dr. Shikha: Yes, India is witnessing active serotype shifts, and they directly explain rising severity, especially in young adults. Initial infection with one of the four dengue serotypes results in lifelong immunity to that specific serotype. Whereas, a secondary infection with a different serotype can trigger Antibody-Dependent Enhancement (ADE).

Young adults who were exposed to one serotype in childhood are now encountering a new dominant serotype, making them especially vulnerable to severe secondary infections.

Q. Is India undercounting dengue cases? Why do so many cases go unreported?

Dr. Shikha: The 2.89 lakh figure in 2023 is what our surveillance system captures, but it is almost certainly a fraction of the true burden. The Lancet has estimated that India accounts for around 33 per cent of the global dengue burden, and globally, we are looking at approximately 400 million infections every year. That puts India's real annual dengue burden potentially in the tens of millions — not hundreds of thousands.

Few studies have shown that the estimates of actual cases are approximately 282 times higher.

There are several reasons why cases go unreported, and they compound each other.

• A large proportion of infections are either asymptomatic or present as a generic fever — patients never seek formal care.
• Our surveillance system is passive and fragmented. Reporting is largely dependent on public health facilities.
• Confirmatory testing through NS1 antigen tests or PCR requires infrastructure that is not yet uniformly available at the primary health center level, particularly in rural and semi-urban areas.

Q. Are previously dengue-free regions in India now reporting cases due to climate change?

Dr. Shikha: Yes, the geographic spread is both significant and well-documented. Climate change is playing a major role in this shift. Rising temperatures, changing rainfall patterns, increasing humidity, and rapid unplanned urbanization are creating more favorable conditions for Aedes aegypti mosquitoes to survive and transmit the virus for longer periods each year.

Since the mid-1990s, dengue has rapidly spread to regions where it was historically non-existent, including Odisha, Arunachal Pradesh, and Mizoram. In the early 2000s, dengue was endemic only in a few southern and northern states; it has since spread to many states, including union territories.

Read More: Ebola Outbreak: Rare Bundibugyo Strain Confirmed In DR Congo And Uganda

The shift is particularly visible in hilly and cooler geographies such as Himachal Pradesh and Jammu & Kashmir. Climate modelling projects further expansion of Aedes albopictus into upper Himalayan regions, including Leh-Ladakh and Arunachal Pradesh, by 2050.

Q. What are the biggest challenges in indigenous dengue vaccine production in India?

Dr. Shikha: India has strong vaccine manufacturing capacity, but dengue remains scientifically complex. Existing vaccines have limitations and do not cover all vulnerable groups.

India’s first Phase 3 trial for an indigenous dengue vaccine, DengiAll, is underway across 18 states. The Butantan vaccine candidate, originally developed by NIH, has been licensed to Indian companies, including Panacea, SIIPL, and Indian Immunologicals, with the ICMR-Panacea candidate being the most advanced.

The recent DCGI approval of Qdenga is encouraging, but sustained financing and coordination between ICMR, DBT, and industry will be critical for developing a truly indigenous vaccine.

Dengue has become one of the fastest-emerging health crises in the urban parts of India. Every year during the monsoon season, the number of dengue cases rises dramatically in many Indian cities, posing a huge burden on the healthcare sector.

Though climate and mosquitoes are usually cited as reasons for the surge in dengue cases, the problem actually lies in how urban life and the infrastructure of the cities have changed over the decades.

Why Urban Areas Are More Vulnerable

The dengue virus is spread through the Aedes aegypti mosquito that lives well in fresh still water, which is abundant in urban areas.

Mosquitoes breed in construction sites, open water tanks, old plastic buckets, flower pots, coolers, water stored on roofs, and blocked drainage systems. Due to the growing size of cities and high population density, mosquito-borne diseases have become more common.

There are many factors that contribute to the rise in the number of dengue patients, one of which is unplanned city expansion. The fast pace of development in the cities results in stagnant water in the construction areas going unnoticed for weeks.

Moreover, improper drainage and a lack of sanitation facilities help mosquitoes breed. Even posh societies and offices can suffer if proper checks are not conducted.

Urban lifestyle trends also act as indirect factors contributing to the issue. Longer working hours, higher levels of indoor activities, and reliance on mechanical ventilation lead to less focus on environmental hygiene issues.

Families tend to take mosquito prevention steps only after an outbreak starts. The overuse of plastics and poor waste management practices in urban areas have exacerbated waterlogging problems.

The situation has been exacerbated by climate change and global warming. Mosquitoes can breed at a faster pace and survive for a longer period of time in the warm climate and unpredictable rain patterns. Another factor that plays an important role is urban heat islands, which refer to places that are hotter because of man-made concrete buildings.

What Needs to Change?

In order to curb the incidence of dengue, there must be an all-around transformation, both on the part of the governing authorities and the people. Firstly, urban planning should take into consideration good drainage facilities, frequent fogging, garbage disposal services, and proper regulation of building sites. Secondly, there must be frequent checks in residential areas, schools, offices, markets, and open public areas.

Secondly, the awareness campaign needs to be practical and more community-oriented. The citizens should realize that the prevention of dengue starts from their homes. Actions like washing the coolers once a week, covering the water tank, not allowing the water to stagnate, and using mosquito repellents will go a long way in minimizing the spread of dengue.

Early Detection and Healthcare Preparedness

Healthcare preparedness is also equally important. The early detection and proper treatment of dengue could help avoid any serious complications. One should never overlook symptoms like fever, body pain, headache, rashes on the skin, nausea, and weakness during the rainy season.

Combatting dengue fever is no longer just a matter of health care but rather a question of urban planning and lifestyle issues. As the cities continue to expand, everyone should unite and come up with healthier and more environmentally friendly cities. Otherwise, we may see more recurring problems of dengue outbreaks in urban settings every year.

Amid growing discussions around hantavirus transmission through body fluids, experts today stressed that cases involving transmission through breast milk or semen remain extremely rare and should not trigger unnecessary panic.

The discussions began after a 2023 study published in the journal Viruses found that the Andes strain of the rat-borne virus can persist in human semen for up to six years.

More concerning was the possibility that the virus could potentially be transmitted sexually even after a person has recovered, according to the peer-reviewed study.

The research, conducted by Swiss scientists at Spiez Laboratory, suggested that hantavirus may survive in the male reproductive tract like viruses such as Ebola.

“Taken together, our results show that the Andes virus has the potential for sexual transmission,” the study said. However, to date, no confirmed case of such transmission has been documented.

Why Viral RNA Can Persist In Semen

Speaking to HealthandMe, Dr. Rajeev Jayadevan, convenor of the IMA research cell, explained that the detection of Andes virus RNA — the hantavirus strain linked to the recent MV Hondius cruise ship outbreak — in semen long after recovery is not entirely unexpected.

“The finding of RNA belonging to the Andes virus in human semen long after recovery is no surprise. In fact, this is a well-described scenario in at least 27 different viruses, including Zika and Ebola,” he said.

He explained that viruses reaching the testis enter what is known as an “immune-privileged” site protected by the blood-testis barrier (BTB).

“The testis is naturally shielded from the body’s immune system to protect newly formed sperm cells from being recognised and destroyed as ‘foreign’,” Dr. Rajeev said.

According to the expert, many viruses take advantage of this natural immune protection, allowing them to remain in the area longer than expected.

However, he clarified that although researchers detected viral RNA in semen, the virus itself could not be cultured, meaning there is no proof that the infectious virus remained present.

Also read: Ebola Outbreak: Rare Bundibugyo Strain Confirmed In DR Congo And Uganda

Can Hantavirus Spread Via Breast Milk?

Another study published in Emerging Infectious Diseases, a monthly open-access peer-reviewed medical journal published by the US Centers for Disease Control and Prevention, highlighted the risk of mother-to-child transmission of the Andes strain of hantavirus through breast milk.

Andes virus (ANDV) is the only hantavirus known to spread between humans through close contact.

“We detected the genome and proteins of ANDV in breast milk cells from an infected mother in Chile who transmitted the virus to her child, suggesting gastrointestinal infection through breast milk as a route of ANDV person-to-person transmission,” the study said.

Epidemiologist Dr. Amitav Banerjee, professor at DY Patil Vidyapeeth, Pune, told HealthandMe that while isolated cases of hantavirus transmission from mother to child through breast milk have been reported, they are highly uncommon.

“These cases of hantavirus transmission through breast milk from mother to child are very rare. As a general rule, there is no need to worry excessively,” he said.

According to him, mothers experiencing fever during the acute stage of illness may temporarily avoid breastfeeding because viral load tends to be highest during active infection and just before symptoms appear. However, he stressed that breastfeeding should not be stopped routinely out of fear.

Dr. Amitav explained that the situation is somewhat comparable to HIV transmission through breast milk, which also occurs in less than 1 percent of cases. Despite that, mothers in many developing countries are still advised to continue breastfeeding because the health risks of depriving infants of breast milk are often greater than the risk of viral transmission.

He noted that hantavirus differs significantly from HIV because it is generally an acute and transient infection, unlike HIV, which persists lifelong in body fluids.

“Hantavirus infection is acute and transient, whereas HIV is lifelong,” he said, adding that hantavirus usually clears from the body after recovery, including from semen and other body fluids.

Sexual Transmission After Recovery Still Unclear

Dr. Rajeev noted that the Andes virus spreads primarily through close contact and shared personal space while a patient is symptomatic.

“Whether it can be sexually transmitted long after recovery remains unknown,” he said.

Overinterpreting RT-PCR Results

Dr. Amitav also cautioned against overinterpreting isolated reports of viral detection in semen or breast milk.

According to him, RT-PCR tests are extremely sensitive and may detect dead viral particles even after the infection has resolved. Therefore, a positive RT-PCR result does not necessarily mean that a person remains infectious.

“In fact, RT-PCR is highly sensitive and often used more for research and surveillance purposes. Detecting viral material does not always indicate active infection or transmission risk,” he said.

He added that hantavirus does not appear to persist as an infectious virus for a long period after recovery and that there is currently no strong evidence supporting long-term transmission once a patient has recovered.