It’s well known that exercise is good for health and helps to prevent serious diseases, like cancer and heart disease, along with simply making people feel better overall. However, the molecular mechanisms responsible for preventing cancer or slowing its progression are not well understood. But, a new study, published in the Proceedings of the National Academy of Sciences, reveals how exercise can increase glucose and oxygen uptake in the skeletal and cardiac muscles, instead of allowing it to “feed” tumors.

Reduced tumor growth in exercised mice

To study how exercise-induced metabolic changes affect tumor growth, the research team injected mice with breast cancer cells and fed some of the mice a high-fat diet (HFD), consisting of 60% calories from fat, while others were fed a normal diet as a control. The HFD mice were given running wheels for exercise, although exercise was voluntary. The team used stable isotope tracer studies [U-13C6] glucose and [U-13C5] glutamine to track metabolic changes.

After 4 weeks of wheel running, the team found a significant difference in tumor sizes between mice that chose to exercise, compared to those that did not—even when they were fed the same diet.

The study authors write, “Obese mice which underwent 4 weeks of voluntary wheel running after tumor injection exhibited nearly a 60% reduction in tumor size. The exercised mice had greater lean mass and lower fat mass than their nonexercised, obese counterparts, with plasma glucose and insulin concentrations comparable to the sedentary chow fed controls.

“After a 30-min bout of acute moderate intensity (15 m/min) treadmill exercise, the exercised obese mice had higher cardiac and skeletal muscle 2-deoxyglucose uptake and reduced tumor glucose uptake.”

The researchers also analyzed exercise-induced changes in mice with a type of melanoma that is typically not exacerbated by obesity (in contrast to breast cancer). Still, after four weeks of exercise, obese mice with melanoma had significantly smaller tumor sizes, along with reductions in tumor glucose uptake and oxidation compared to the sedentary controls. These results suggest that the shift in glucose (and thus the slowing of tumor growth) is not tumor-type specific.

Some mice also underwent “prehabilitation”—exercise undertaken before tumors were introduced. Similar beneficial results were found in these mice. The study authors explain, “These observations may be due to an earlier achievement and maintenance of body composition or overall fitness (VO₂ peak) with early exercise exposure.”

Exercise-induced metabolic changes

The repartitioning of glucose to cardiac and skeletal muscles instead of tumors appears to play a major role in slowing tumor growth, but there are other changes taking place, as well. The team also found 417 genes related to energy metabolism and other metabolic pathways that were expressed differently between exercised and sedentary lean mice.

The team says that a downregulation in a protein referred to as mTOR, is seen in the exercised mice and this may be helping to slow tumor growth, along with processes like shifts in the use of amino acids, which tumors have been documented to utilize.

Does exercise slow tumor growth in humans?

The team also gathered gene expression data from another study, which analyzed exercise training in women with breast cancer and a metaanalysis of skeletal muscle responses to multiple types of acute and chronic exercise. The data revealed an upregulation in the glutamine and leucine channeling genes in the muscle tissue of humans who exercise. They say that no distinct differences were observed in the expression pattern of these genes when comparing exercise intensity, which may be due to the small sample size or the limited number of analyzed genes.

So, more research is certainly required, but since metabolic pathways are similar in humans, mice, and other mammals, there is likely a similar relationship between exercise and tumor growth in humans. This would be in line with other studies indicating tumor suppression with the help of exercise in humans.

Overall, researchers remain optimistic about exercise in the role of cancer treatment in humans. A better understanding of how glucose is utilized after exercise in humans with tumors can inform prehabilitation strategies for cancer patients, help doctors integrate fitness into cancer therapies, and potentially assist researchers in identifying new therapeutic targets.

“We anticipate that this work may lay the groundwork to reveal key insights into the role of systemic adaptations to exercise in broader antitumor therapies. Further, examination of the role of fitness on the molecular pathways altered by exercise may uncover new therapeutic targets in precision oncology, particularly in patients who cannot tolerate exercise,” the study authors explain.

California State University, Sacramento, researchers traced how disordered childhood social worlds in women connected to faster life history traits and greater mating effort, with those traits explaining 22.2% of the association between childhood microsystems and adult sexual behavior.

Childhood environments and strategies

Life History theory treats childhood ecology as a starting point for strategies that govern survival, mating effort, and parental effort. Mating effort involves behavior that increases access to sexual opportunities, while parental effort involves investing time and resources so children survive to reproduce.

Faster strategies align with earlier sexual debut, more short-term mating, more lifetime partners, and more offspring at younger ages. Slower strategies align with later sexual debut, safer reproductive behavior such as monogamy and contraceptive use, fewer lifetime partners, and greater parental investment.

Childhood harshness and unpredictability show up in prior work through divorce, parental job loss, frequent moves, unsafe neighborhoods, and parental substance misuse or violence. Supportive and predictable childhood environments appear with nurturing parents, stable housing, and safer neighborhoods.

Bioecological theory describes environmental layers that interact with the child over time. Microsystems contain parents, extended family, teachers, and neighbors who interact frequently and reciprocally with the child. Exosystems include factors that affect the child indirectly, such as parental employment or frequent moves.

Prior studies linked parental disengagement, father absence, and neighborhood violence to short-term mating, early sexual debut, and sexually risky behavior in adolescence and adulthood. Harsh and unpredictable environments relate to present-oriented thinking and impulsivity, which then link to risky sexual behavior. Dark Triad traits, including psychopathy and Machiavellianism, support resource control, low self-control, and mating effort, along with sexually risky behavior.

Slower profiles are associated with traits such as long-term planning, agreeableness, conscientiousness, mental and physical health, well-being, self-esteem, positive affect, and emotional intelligence.

In the study, “Using SEM to test the associations among women’s childhood ecology, adult psychosocial life history traits, and mating effort,” published in Evolution and Human Behavior, researchers used structural equation modeling to investigate how childhood microsystem and exosystem experiences, adult psychosocial traits, and mating effort fit together in women.

Participants were 875 ethnically mixed, self-identified female undergraduate college students at a university in Northern California. Ages ranged from 18 to 46 years, with a mean age of 20.55. Questionnaires included childhood ecology, adult psychosocial traits, and mating effort along with Adverse Childhood Experiences (ACE) Inventory, a 20-item checklist of hardships in childhood.

Childhood trauma, control, and partners

Correlations between microsystem indicators, faster traits, and mating effort unpacked those paths. Higher microsystem scores related to higher ACE scores, paternal and maternal disengagement, more parental cohabitation, and higher neighborhood crime. Higher microsystem scores also related to higher, faster scores and Dark Triad psychopathy, higher coercive and power-seeking resource control, higher Machiavellianism, and lower self-control.

Psychopathy showed strong links to mating effort. Higher psychopathy correlated with more lifetime sexual partners, stronger short-term mating orientation, and greater future sexual risk intentions. Machiavellianism correlated with stronger short-term mating orientation and greater future sexual risk intentions.

Self-control scores related inversely to harsh childhood conditions. Higher ACE scores and more neighborhood crime correlated with lower self-control. Lower self-control correlated with more lifetime sexual partners, more openness to casual sex, and higher future sexual risk intentions.

Resource control strategies formed another bridge. Neighborhood crime correlated with higher coercive and power-seeking resource control. Higher coercive and power-seeking scores correlated with more partners, stronger short-term mating orientation, and higher future risk intentions.

Higher neuroticism correlated with higher ACE scores, more neighborhood crime, higher father disengagement, stronger short-term mating orientation, and greater future sexual risk intentions.

Sexual start patterns

Age at first sexual encounter could not be included in the structural equation model because a substantial number of participants reported no sexual experience. 284 women reported never having sex, leaving 591 with a reported age at sexual debut. A hierarchical multiple regression used microsystem, exosystem, slower traits, and faster traits as predictors of age at sexual debut in that subgroup.

Women who grew up in more chaotic or troubled family and neighborhood environments tended to start having sex at younger ages. Broader issues such as money instability and slower life history traits did not change that pattern much.

Women with higher adversity scores, more disengaged fathers, more non-relatives living in the home, higher psychopathy, a stronger drive to control others and resources, and higher neuroticism reported younger ages at first sex.

Mothers

A total of 33 participants reported having children. For this analysis, 37 participants without children were randomly sampled to form a comparison group of 70 women.

Microsystem and exosystem scores did not significantly predict having children. Slower and faster traits did. Women in this small subgroup who showed more of the slower life history traits (things like resilience, well-being, conscientiousness, secure attachment, and grit) were more likely to have children than women with lower scores on those traits.

Women in this small subgroup who had children differed from those without children mainly in their adult traits, not in their reported childhood environments. Mothers tended to score lower on fast life history traits such as psychopathy, low self-control, and power-seeking, and higher on slow traits, while the childhood microsystem and exosystem scores did not clearly separate mothers from non-mothers.

Life history patterns and implications

Psychosocial life history traits clustered into two partly independent sets, one faster and one slower. Faster traits were linked both to harsher childhood microsystems and to higher mating efforts, many of which are explicitly risky or short term. Slower traits were linked to kinder childhood microsystems, and showed statistically non-significant associations with mating effort.

Microsystem conditions before age 10 are linked more strongly to psychosocial traits and mating effort than exosystem conditions. Childhood trauma, parental disengagement, parental cohabitation with non-kin adults, and neighborhood crime all clustered within higher microsystem scores and connected to faster traits, more partners, shorter-term mating orientation, and higher future sexual risk intentions.

Perceived resource inconsistency in the exosystem added further associations with partner counts, short-term orientation, and risk intentions.

Conclusions, limitations and open questions

Results showed that the childhood microsystem had a far greater impact than the external environment on personality development and mating strategies. Good parenting and a protective early environment that allowed security and predictability showed a trajectory of positive associations.

The cohort included only college students, a major limitation for generalizing the findings, as college attendance is conceivably a measurable outcome of Life History theory. How the findings might compare to women who did not attend college, and how this socioeconomic cutoff might alter the strength of the associations is unclear.

The health benefits of nature are well-known, but its role in encouraging day-to-day physical activity across different regions and demographics has been less clear. This question carries new urgency as the world faces a “physical inactivity pandemic,” with trends especially stark in the United States, where many people fall short of recommended activity levels.

To investigate how urban green spaces influence movement, researchers with the Stanford-based Natural Capital Project (NatCap), a global alliance focused on valuing nature’s benefits to people, analyzed wearable step-counter data in their new study published in Nature Health. They found that higher park accessibility, not simply more greenery, is associated with higher daily activity.

“Greenness alone doesn’t seem to encourage movement,” said Youngeng Lu, lead author of the paper, who did the work while he was a postdoctoral scholar at NatCap. “Even if you have lots of trees or vegetation, if you can’t easily reach them, it doesn’t translate to more physical activity. Accessibility to parks was the factor that mattered most.”

Measuring movement at scale

Past research links nature to physical activity, but many studies rely on self-reported data, focus on only a few cities, or track people for short periods. Those constraints limit how broadly the findings can be applied.

To take the next step in understanding these patterns, the team used multi-year wearable-device data from the All of Us Research Program, a national health initiative. Participants volunteered their Fitbit records, giving researchers three years of daily step counts and activity intensity from 7,013 anonymous users in 53 U.S. metropolitan areas. The team then used modeling that accounted for variations between individual people and cities to test how activity levels shifted with different types of urban nature.

The researchers distinguished between two aspects of urban nature: total greenness (measured from satellite imagery and including forests, gardens, and other vegetation) and park accessibility, which encompasses park existence, distance from population centers, and connectivity to one another. Using participants’ home locations, the team calculated how easy it is for residents to travel to nearby parks on foot.

Although overall greenness didn’t appear to be linked with higher physical activity, park accessibility was a strong predictor of movement. A 10% increase in park accessibility corresponded to roughly 107 additional steps per day.

Who benefits most?

The multi-year dataset allowed researchers to examine how the benefits of park access vary by region and demographic group over time. They also considered variables such as temperature, precipitation, population density, city walkability, and air quality, revealing some telling patterns in the game of step tracking.

Western and southern cities showed stronger links between park accessibility and movement, a trend the team suspects may be influenced by climate, culture, or outdoor habits. Lu emphasized the significant role temperature played in daily step counts. In mild climates, park accessibility had a much stronger effect on physical activity than in cities that are extremely hot or cold, where conditions are less favorable for outdoor exercise.

Demographic trends were also clear. Non-white residents, older adults, and people who were less active at baseline experienced the greatest increase in activity when parks were easier to reach. These results support the “equigenic effect,” in which improved access to green space disproportionately benefits more vulnerable communities.

“For non-white and lower-income neighborhoods, even small increases in park accessibility can encourage significantly more activity,” Lu said. “Parks need to be accessible to everyone, not just higher-income, white populations.”

Designing healthier cities

The study suggests that building new parks isn’t the only way for cities to increase the physical activity of their residents. Enhancing access to existing parks by improving walkability, removing barriers, and connecting parks to nearby neighborhoods (such as creating pedestrian overpasses) can also deliver public health benefits.

“It’s promising from a health perspective,” said Lisa Mandle, senior author on the paper, and director of science-software integration and lead scientist with NatCap. “Investing in access helps residents be more active and promotes equity in urban health.”

Lu added that the priority now is ensuring that the benefits of park access are shared equitably across cities. Future research could track changes in accessibility over time, incorporate GPS data to measure actual park use, and recruit more diverse participants to strengthen the evidence.

By continuing to explore nature’s role in public health, the team hopes to “inform urban planning decisions and inspire interventions that make cities healthier, greener, and more equitable for everyone,” Lu said.

“This study arose out of our efforts to understand how parks and nature in cities can benefit the people living there,” said Mandle. “We know green spaces provide mental health benefits, but we wanted to look more closely at physical activity, and specifically, who benefits most and in what contexts.”

This aligns with the broader goals of NatCap: “to advance understanding of the diversity of ways that nature benefits people in order to incorporate these values into decision-making,” Mandle said.

Electrotherapy using injectable nanoparticles delivered directly into the tumor could pave the way for new treatment options for glioblastoma, according to a new study from Lund University in Sweden.

Glioblastoma is the most common and most aggressive form of brain tumor among adults. Even with intensive treatment, the average survival period is 15 months. The tumor has a high genetic variation with multiple mutations, which often makes it resistant to radiation therapy, chemotherapy and many targeted drugs. The prognosis for glioblastoma has not improved over the past few decades despite extensive research.

How electrotherapy targets tumors

Electrotherapy offers another strategy to combat solid tumors. Using short, strong electric pulses (irreversible electroporation), non-reversible pores are created in the cancer cells leading to their death. The body’s immune system is simultaneously stimulated.

The problem is that surgery is required to place the stiff metal electrodes that are necessary for the treatment. In sensitive tissue, in the brain for example, this often entails a very difficult procedure, which has led to strict criteria regarding which patients can be treated.

Johan Bengzon is a researcher in glioblastoma and adjunct professor at Lund University, and consultant in neurosurgery at the Skåne University Hospital. He regularly treats patients with glioblastoma and is frustrated by the limited treatment options.

“The short distance between the hospital and the University in Lund facilitates cooperation and that’s why I contacted research colleagues to find out if injectable electrodes could be an alternative solution in electrotherapy,” says Johan Bengzon.

Injectable nanoparticles as a new approach

The research team, with Amit Singh Yadav, Martin Hjort, and Roger Olsson at the helm, had previously used nanoparticles to form injectable and electrically conductive hydrogels to control brain signaling and heart contractions. It is a minimally invasive method in which the particles are injected using a thin syringe directly into the body.

The particles break down after the treatment and thus do not need to be surgically removed. Perhaps the same technology could be used to destroy tumor cells in glioblastoma.

“After surgical treatment, unfortunately the glioblastoma tumor often returns on the outer edge of the area operated on. By drop casting the nanoparticles into the tumor cavity after an operation, we could electrify the edges while the immune system is also activated. In animal models, the procedure, due to this irreversible electroporation, led to tumors being wiped out within three days,” says Olsson, professor of chemical biology and drug development at Lund University, who led the study.

Early results and future prospects

The prospects are good and the researchers are very hopeful for the future, even though there is a long way to go before it becomes a clinical reality. The challenge is now to test the method on larger tumors.

“We have seen that the electrode is well received in the brain. We have not noted any problems relating to side effects and after 12 weeks the electrode disappeared by itself as it’s biodegradable. The technology combines direct tumor destruction with activation of the immune system and can be an important step towards more effective treatment of glioblastoma,” concludes Singh Yadav, researcher at Lund University and first author of the study.