Rosalba (Rose) Hernandez, a professor of social work at the University of Illinois Urbana-Champaign, led the research team. The group reviewed results from 18 randomized controlled trials that tested positive psychology and mindfulness interventions designed to improve mental or physical health.

How the Heart Health Programs Worked

The programs varied widely in how they were delivered. Some relied on structured phone sessions, journaling paired with brief check-ins, or digital tools such as apps and text messages. Others involved interactive in-person group meetings or hybrid approaches that combined face-to-face activities with online tools and virtual sessions.

Most programs included weekly sessions along with activities participants completed at home to reinforce what they had learned. The majority lasted between six and 12 weeks.

The studies generally enrolled groups of 50-200 adults who already had elevated cardiovascular risk, including uncontrolled hypertension, heart failure, or other health conditions. Participants were usually in their late 50s to mid-60s. Among studies that reported gender, women made up 35-55% of the participants.

“In hypertension and postacute coronary syndrome cohorts, mindfulness-based programs delivered over an eight-week period reduced systolic blood pressure and lowered inflammatory markers such as high-sensitivity C-reactive protein and fibrinogen,” said Hernandez, who is a Fellow of the American Heart Association. “A 12-week spirituality-based digital intervention achieved one of the largest reductions — reducing systolic blood pressure measured with a standard cuff by 7.6 points, and central systolic pressure — which is measured in the aorta as it leaves the heart — by 4.1 points.”

Finding the Right “Dose” of Positivity

Previous research on positive psychology often did not clearly establish how frequently people needed to practice these techniques, or for how long, to gain health benefits, Hernandez said. Her team wanted to determine what level of participation was most consistently associated with improvements in cardiovascular health.

The review showed that programs with more frequent participant contact tended to produce the most reliable physiological benefits. Hernandez said this finding highlights the potential value of incorporating positive psychology strategies into long-term cardiovascular treatment and prevention.

The strongest behavioral changes came from an eight-week WhatsApp-based program that paired weekly sessions with daily microtasks. Participants were encouraged to become more physically active, improve their diets, and take their medications as prescribed.

Another program that incorporated motivational interviewing increased cardiac patients’ activity by 1,800 steps per day while also improving medication adherence. By comparison, the mindfulness programs improved physical activity and diet, but did not produce the same medication adherence benefit, according to the study.

“The therapeutic dose that was most consistently linked with improvements in blood pressure, inflammation and endothelial function was daily practice reinforced by weekly sessions over eight to 12-week periods,” Hernandez said. “Therapeutic dosing typically involved high-frequency dosing over this time period to obtain short-term physiologic benefits, while ongoing less-intensive contact may be needed to sustain behavioral change.”

Mental Health as Part of Heart Care

The study was published in the journal Cardiology Clinics. Co-authors included University of South Florida social work professor Soonhyung Kwon; Alyssa M. Vela, a professor of surgery and of psychiatry and behavioral sciences at Northwestern University Feinberg School of Medicine; and Katharine S. Edwards, a professor of cardiovascular medicine and of psychiatry and behavioral medicine at Stanford Medicine.

“The findings of this study further point to the importance of attending to mental and behavioral health for cardiovascular disease prevention and cardiovascular health optimization,” Vela said. “This speaks to the need for routine screening and integration of cardiac behavioral medicine to allow for access to important interventions.”

The findings contribute to a growing body of evidence connecting psychological well-being with cardiovascular protection. Traits and experiences such as optimism, positive affect, and gratitude have increasingly been associated with healthier hearts.

Earlier Research Linked Optimism to Healthier Hearts

The new work builds on a prior study led by Hernandez, which found that people with the highest levels of optimism tended to have healthier hearts. That research was published in the journal Health Behavior and Policy Review.

That earlier study was funded by the National Institutes of Health and the National Center for Research Resources. It was co-written with preventive medicine professors Kiarri N. Kershaw, Juned Siddique and Hongyan Ning, all of Northwestern University Feinberg School of Medicine; preventive medicine and epidemiology professor Donald M. Lloyd-Jones of Boston University Chobanian and Avedisian School of Medicine; psychology professor Julia K. Boehm of Chapman University; social and behavioral sciences professor Laura D. Kubzansky of Harvard University School of Public Health; and Distinguished Professor of Epidemiology Dr. Ana Diez Roux of Drexel University.

The findings, published in Current Biology, suggest that the spiral forms as the embryo’s body rapidly lengthens while its gut acts as a tether. That physical constraint causes the growing body to buckle and twist into a right-handed coil.

“It’s like when you adjust the length of a strap and the longer, buckling side of the loop twists,” explains senior author and team leader Dr. Tetsuto Miyashita, evolutionary biologist at the Canadian Museum of Nature.

Why Spirals Form in Nature

The discovery adds snake embryos to a long list of naturally occurring spiral structures that scientists are still working to understand.

“There is a touch of mystery to spirals, and we are only beginning to understand how these shapes are produced in animals, such as our looping intestine, snail shells, and now these beautifully coiled snake embryos,” says lead author Alexandra Weber, now a graduate student in zoology at the University of British Columbia.

Adds Miyashita: “These puzzles beckon our curiosity. After all, spiral forms in nature have inspired human creations ranging from rotini pasta, to a barber’s pole or even portrayals of the biblical ‘Tower of Babel’.”

The project itself grew out of an unusual circumstance. During the COVID lockdown in 2020, Miyashita was working from home and looking for a research question his students could investigate without access to laboratories or museum collections.

“Then the lightbulb turned on. I had inherited from my PhD advisor this fascination with asymmetries in animal forms. So every time I saw images of snake embryos in papers, I wondered whether they are right- or left-handed in their coiling.”

That question became the foundation of the study.

More Than 900 Snake Embryos Examined

Miyashita asked Weber, who was then at Carleton University, along with two undergraduate students at the University of Ottawa, to search published research and museum databases for photographs of developing snakes.

“We obtained pictures for more than 900 embryos from 39 snake and other limbless squamate species. That’s a statistically robust sample.”

A clear pattern emerged. During the first several weeks after the eggs were laid, the embryos appeared to coil only dextrally, meaning to the right, as viewed from head to tail.

“At these stages, the embryos don’t have muscles to move with, so different forces are making them coil right-handed,” Weber explains. “But we didn’t know what’s making them do that.”

Because the embryos were not yet capable of actively moving their bodies into position, the researchers suspected that some physical feature of their development was creating the twist.

CT Scans Reveal a Hidden Gut Structure

A crucial clue came from Dr. Raul Diaz, a collaborator at California State University Los Angeles. Diaz used CT imaging to examine snake embryos in greater anatomical detail.

The scans revealed an unexpected arrangement inside the developing animal.

“Raul’s CT scan of a snake embryo revealed a structure we had never seen before ¾ it was a pillar of gut stretching through the spiral of the coiling body,” Miyashita says. “There’s an intestine detached from the rest of the body, surrounded by tendrils of blood vessels from the yolk.”

That observation gave the team the mechanism they had been searching for.

Snake embryos must lengthen rapidly to produce their unusually elongated bodies, but the gut does not grow at the same rate. The mismatch in growth creates a mechanical constraint that helps force the body into a spiral.

“So they detach the slow-growing gut, which is now tethering the lengthening body. The body buckles and twists into coiling,” Miyashita explains. “This coiling force is directed so the embryos grow to the opposite side of the yolk. And the yolk is always to the left side of the embryo, hence the embryo will always start coiling right-handed.”

Why the Coiling Direction Later Changes

The embryos do not remain locked into this right-handed arrangement throughout development. As they grow, the yolk becomes smaller, and the embryos gain more room to shift position. Their muscles also mature, allowing them to begin moving on their own.

“Some remain in right-handed coils, but some recoil to the left side,” Weber says. “So half of these near-hatching embryos are right-handed and the other half left-handed.”

The results suggest that the earliest direction of coiling is imposed by developmental anatomy and physical forces rather than by deliberate muscular movement.

For Miyashita, the discovery also illustrates how a simple observational question can lead to a broader biological insight.

“Scientists have long been fascinated with how and why snakes evolved their strange body form. To answer that question, they tended to take a deep dive into sophisticated genetic research, looking at Hox genes, enhancers, and so on,” he says. “These are key discoveries. But here, out of the COVID lockdown, we uncovered a snake’s secret with a startlingly simple approach — just scroll through an album of snake embryos and record which way they are coiled, and take a good look at their anatomy.”

A New Model for Spirals in Biology

The researchers believe the same general model could eventually help scientists investigate other spiral-shaped structures found in living organisms.

“We are now opening the possibility to develop this model further to explain other spiral forms in nature,” he adds.

Weber agrees: “This all started out with a curiosity to see if snakes are ‘handed’. It was exciting to follow it to deep insights about their evolution.”

The study team consists of scientists, students, and professors from the Canadian Museum of Nature, the University of British Columbia, Carleton University, the University of Ottawa, California State University Los Angeles, and the University of Helsinki.

The OLI (Operational Land Imager) aboard the NASA USGS Landsat 8 and Landsat 9 satellites documented the dramatic change in images taken on August 6 and August 14, before and after a stretch of severe weather, respectively.

The views provide a close look at the Chajnantor plateau within the Altiplano-Puna volcanic complex. This high-elevation area is home to the Atacama Large Millimeter/submillimeter Array (ALMA), one of the most powerful radio telescopes in the world. As heavy snow and strong winds moved through the area, ALMA suspended operations and placed its antennas into a protective survival mode.

Conditions became even more unusual later in the month. A second storm spread fresh snow across a much broader part of northern Chile. An August 19 image from the MODIS (Moderate Resolution Imaging Spectroradiometer) aboard NASA’s Terra satellite shows snow reaching westward from the Andes, crossing the hyperarid heart of the Atacama, and approaching the Pacific coast south of the Chilean port city of Antofagasta. Several other major astronomical observatories are located in this coastal region, and some also suspended operations while the storm passed.

An Unusual Atmospheric Setup

Much of the winter precipitation that reaches this part of Chile is associated with cutoff lows, low-pressure systems that separate from the jet stream and can sometimes move into northern Chile. René Garreaud, an atmospheric scientist at the University of Chile, said this type of system was responsible for the notable snowfall in 2025.

A cutoff low was also behind the late August 2026 storm, but this event developed under more unusual circumstances. The system broke away from an exceptionally large trough, an elongated region of relatively low atmospheric pressure, that extended across a huge portion of the Southern Hemisphere from the southern tip of South America into the subtropics.

Combined with plentiful moisture near the coast, this disrupted weather pattern generated precipitation across an exceptionally broad area. Rain and snow fell offshore, along the coastline, through the center of the Atacama Desert, and over the Andes. Garreaud said precipitation totals reached levels “rarely seen in the otherwise extremely arid region.”

Months of Rain in Just Three Days

Not all of the precipitation arrived as snow. Along parts of Chile’s northern coast, it fell as heavy rain. In Taltal, nearly 40 millimeters (1.6 inches) accumulated over three days. According to Garreaud, that amount is roughly 10 times the city’s average annual rainfall.

“We see these kinds of events only a few times, if any, per decade.”

The intense precipitation had serious consequences. Mudflows and flash flooding struck parts of northern Chile, causing widespread disruption and damage. The National Disaster Prevention and Response Service (SENAPRED) reported that thousands of people were affected and hundreds of homes suffered major damage.

El Niño Sets the Stage for a Wetter Winter

Garreaud pointed to the strengthening El Niño as an important backdrop to the unusually wet winter unfolding across north-central Chile. The August storms were not the first major events of the season. A major event in July also produced significant impacts in Chile’s Norte Chico region.

During El Niño, the subtropical Pacific high, which ordinarily helps maintain dry conditions over the region, becomes weaker. At the same time, a blocking high is more likely to develop over the South Pacific near the southern end of the continent. Together, these atmospheric changes shift the Southern Hemisphere storm track closer to the equator, making it easier for powerful weather systems to reach areas of Chile that are normally extremely dry.