Researchers at Rockefeller University compared how the body responds to exercise performed at different intensities. They found that six 30-second, all-out sprints changed nearly one-quarter of the proteins measured in the blood immediately after exercise. By comparison, 90 minutes of continuous moderate cycling altered less than one-quarter of one percent. Moderate treadmill running affected more proteins than cycling, but still far fewer than the brief sprint session.

Sprinting Triggers a Rapid Molecular Surge

The sprint workout also altered more than 200 metabolites and rapidly increased levels of proteins involved in blood vessel growth, tissue remodeling, and hormonal signaling.

Some of these proteins appeared to reach the bloodstream through a fast cell-signaling process called ectodomain shedding — rather than being newly produced and released, pieces of proteins already located on the surface of cells were cut away and rapidly sent into circulation.

The researchers also tested how human fat cells responded to blood collected after sprinting. Those cells showed widespread changes in gene activity, including shifts in how they processed fuel, reacted to hormones, and detected nutrient availability.

Moderate Exercise Produces a Slower Response

Moderate exercise led to a much less dramatic immediate reaction. A substantial rise in fatty acids and liver-derived proteins associated with the demands of endurance exercise did not appear in the bloodstream until three hours after the workout.

Human fat cells exposed to blood collected after moderate cycling also showed only small changes in gene activity.

Links to Metabolic Health and Biological Aging

The researchers then compared the proteins that responded to exercise with health information from more than 53,000 participants in the UK Biobank. Many of those proteins were associated with lower risks of cardiovascular and metabolic disease.

The pattern was especially notable for obesity, type 2 diabetes, and other metabolic disorders. Among 33 proteins associated with lower risk, 32 were altered by sprinting, while only three were affected by moderate exercise. More than one-quarter of those proteins were also linked to slower biological aging.

“What’s exciting here is that just a few minutes of intense exercise can trigger a significant molecular response,” says Cohen. “And we still see it after eight weeks of training, which tells us this response isn’t simply a product of the body struggling to keep up with unfamiliar stress. It may be that the responses we observed are intrinsic to intense exercise.”

Why Exercise Intensity May Matter

The findings suggest that exercise intensity may strongly influence the proteins and metabolites released into the bloodstream and, in turn, the way tissues throughout the body respond.

“It’s well appreciated that different intensities of exercise stimulate distinct body-wide adaptations,” notes Luke Olsen, the postdoctoral fellow who conducted the studies. “However, the molecular mechanisms linking these intensity-dependent adaptations have remained largely elusive. Our work suggests that exerkines-proteins and metabolites released into the bloodstream following exercise-are highly sensitive to exercise intensity and may be the key mediators of the health-promoting effects of short bursts of vigorous exercise.”

Materials can behave in unexpected ways after absorbing light. In some cases, light pushes them into photoinduced states with properties that are very different from those they display under ordinary conditions. These states give researchers another way to alter material behavior beyond conventional approaches such as heating or cooling. Learning exactly how they form could be important for developing future photoresponsive materials and advanced optical technologies.

Capturing a Transformation in Femtoseconds

One of the biggest challenges is speed. The first steps in forming a photoinduced state can unfold on the femtosecond (fs) timescale (a millionth of a billionth of a second), making them exceptionally difficult to observe.

To investigate these earliest moments, a team led by Assistant Professor Tadahiko Ishikawa from the Department of Chemistry, School of Science, Institute of Science Tokyo (Science Tokyo), Japan, worked with then doctoral student Samiran Banu (currently a Special Postdoctoral Researcher at RIKEN) and collaborators at Tohoku University and Nagoya Institute of Technology, Japan.

The researchers focused on a metal-organic framework (MOF), a material constructed by connecting metal ions with organic molecules. Their goal was to determine exactly how a photoinduced hidden state develops. The findings were published in the journal Physical Review Letters.

“We found that the photoinduced hidden state forms within 30 fs through a previously unknown intermediate electronic state,” says Ishikawa.

Ultrafast Lasers Reveal a Hidden State

To follow the transformation, the researchers used time-resolved reflectance spectroscopy and ultrashort laser pulses lasting only six fs. The method allowed them to measure how the light reflected by the material changed almost immediately after the MOF absorbed a laser pulse.

With this extremely fine time resolution, the team tracked rapid changes in the material’s electronic behavior. Within 30 fs, its reflectance spectrum shifted dramatically and developed features linked to the appearance of a new optical absorption band. Those changes indicated that the photoinduced hidden state had formed.

Experiments alone, however, could not fully explain what was happening. The researchers therefore combined their measurements with theoretical calculations to reconstruct the sequence of events inside the material.

A Fleeting Electronic State Comes First

The analysis showed that immediately after absorbing light, the material briefly entered an intermediate electronic state. During this moment, electronic bonds between neighboring sites alternated between stronger and weaker in a repeating pattern. This configuration is known as a bond-order wave state.

The state existed only briefly. It was followed by small movements in the positions of atoms within the material, and those structural changes ultimately produced the photoinduced hidden state.

Theoretical calculations also suggested that the newly formed state may be polar. In such a state, positive and negative electrical charges are distributed unevenly across the material. If these photoinduced polar states can be reliably created and controlled, they could provide new ways to manipulate electronic properties using light.

“By revealing intermediate states, our method could help design materials that can be efficiently controlled using light,” explains Ishikawa.

Toward Materials Controlled by Light

Beyond showing how a photoinduced hidden state develops, the research points to a possible strategy for manipulating material properties with extremely short pulses of light. Being able to create and control these temporary states could contribute to new photoresponsive materials designed for high-speed electronics, optoelectronic devices, and other technologies that require precise control over how materials behave.

Future research could extend the same experimental and theoretical approach to other types of materials. By exposing the previously invisible steps that occur during ultrafast transformations, scientists may move closer to designing materials whose properties can be deliberately and efficiently controlled with light.

A new study published in Frontiers in Materials is helping fill that gap. Researchers in France and Croatia analyzed the protective coating on the Roman Republic shipwreck Ilovik-Paržine 1, which sank about 2,200 years ago off the coast of what is now Croatia.

“In archaeology, little attention is paid to organic waterproofing materials. Yet they are essential for navigation at sea or on rivers and are true witnesses of past naval technologies,” said first author Dr. Armelle Charrié, an archaeometrist at the Laboratory of Mass Spectrometry of Interactions and Systems in Strasbourg. “Studying the coatings, we found two different kinds on this vessel: one made of pine tar, also called pitch, and the other of a mixture of pine tar and beeswax. Analysis of pollen in the coating made it possible to identify the plant taxa present in the immediate environment during the construction or repairs of the ship.”

Pine Tar and Beeswax Protected the Hull

The wreck was discovered in 2016, and both the vessel and its cargo have been investigated several times since then. This study is the first to combine molecular and pollen analysis to identify the ship’s coatings and reconstruct the vegetation present when those materials were produced and applied to the hull.

The research was carried out through a collaboration between the Department for Underwater Archaeology of the Croatian Conservation Institute and the ‘ADRIBOATS’ program of the Centre Camille Jullian at Aix-Marseille University in France.

“Some regions throughout the Adriatic have particular characteristics that led local populations to develop a specific shipbuilding style,” said Charrié. “Only studies like ours offer an overview of these traditions which bear witness to genuine know-how and diverse traditions.”

To investigate the coatings, the researchers performed structural, molecular, and pollen analyses. They used methods including mass spectrometry, which can identify and measure unknown substances within complex organic mixtures.

The team analyzed 10 coating samples to determine the biological origins of the natural materials used on the vessel. Molecular fingerprinting revealed compounds associated with pine trees, showing that every sample was dominated by heated coniferous resin or coniferous tar, also called pitch.

One sample, however, contained a different formulation made from beeswax and tar. This mixture – known to Greek shipbuilders as zopissa – improves the adhesive’s flexibility and is easier to apply when hot.

Ancient Pollen Preserved in Sticky Pitch

Because pitch is naturally sticky, it can capture pollen from nearby vegetation and preserve it for long periods. By studying the types of pollen trapped in the coatings and measuring their relative abundance, the researchers were able to narrow down where some of the pitch may have been produced or reapplied during repairs.

The pollen recovered from Ilovik-Paržine 1 pointed to a wide range of environments. Some came from landscapes typical of Mediterranean and Adriatic coasts and valleys, including forests of holly oak and pine as well as matorral – a kind of Mediterranean shrubland – where olive and hazel trees grow.

Alder and ash pollen indicated vegetation associated with riverbanks and seashores, which occur along the coast and in the nearby hinterland. Small amounts of fir and beech were also present. These trees are associated with mountainous terrain and are characteristic of the north-eastern Adriatic coast, where the mountain ranges of Istria and Dalmatia lie relatively close to the sea.

Evidence of Repeated Repairs Across the Adriatic

The analysis also suggests that the vessel received four to five separate batches of coating over time. The stern and central section appear to have been covered with the same material, while researchers identified three distinct coating batches at the bow.

That pattern may indicate that the ship was repaired repeatedly, with materials obtained from different locations around the Mediterranean.

Earlier research on the vessel’s ballast pointed to Brundisium – today Brindisi – on the south-eastern coast of Italy as the place where the ship was built. The new pollen evidence suggests that some of its coatings may also have been applied in that area.

Other layers, however, may have been added along the north-eastern Adriatic coast, close to where the wreck was ultimately found.

“While it seems obvious that ships sailing long distances need repairs, it’s simply not easy to demonstrate this,” concluded Charrié. “Pollen has been very useful in identifying different coatings where the molecular profiles were identical.”