Fitness
Cardiorespiratory and aerobic demands of squat exercise – Scientific Reports
The main questions of our study are to examine the maximal V̇O2 achieved during five sets of squat exercises (10 reps per set, 5 sets, 3 min rest interval, 65% of 1RM) in relation to predetermined V̇O2max and how these values differ according to participants’ training status. Our study showed that the highest V̇O2 was observed during the 5th set of squat exercises, almost reaching 100% of the participants’ predetermined V̇O2max. When the highest V̇O2 values were presented according to training status, participants with higher strength experienced an increase in V̇O2 during squat exercise up to 108% of their V̇O2max, while the highest V̇O2 of participants with lower strength was 93.7% of their V̇O2max, measured immediately after the final set. When the highest V̇O2 during five sets were averaged, participants reached over 90% of their V̇O2max. Regardless of participants’ training status, oxygen demand during squat exercise was extremely high.
An increase in V̇O2 during resistance exercises has been previously reported. However, there are substantial differences in the amount of V̇O2 between our study and previous studies9,19. Previous studies reported V̇O2 during squat exercises ranging from approximately 16 to 31.3 ml/kg/min depending on the length of the rest intervals9,19. In the present study, we observed values above 40 ml/kg/min, and in some participants, V̇O2 increased above 50 ml/ kg/min, exceeding their pre-determined V̇O2max. A significantly greater V̇O2 observed among our participants could be due to training status and the specific exercise protocol. The 1RM among our participants was 141.4 ± 31.3 kg, whereas the 1RM reported by Ratamess et al.9 was 127.9 ± 31.1 kg. Furthermore, Ratamess et al.9 employed higher intensity resistance exercise, set at 75% of 1RM, whereas our study employed a lower intensity, 65% of 1RM. Given that all participants in our study successfully completed 10 reps of squats until the fifth set whereas participants from Ratamess et al.9 did not, the exercise in the current study elicited a higher demand for aerobic metabolism. Another rationale for the relatively higher V̇O2 during our squat exercise could be due to different squat techniques. In the present study, all participants were instructed to perform a full squat with a full range of motion. In contrast, other studies either utilized only half squats or did not specify the depth of the squat. Performing full squatting is likely to elicit a higher oxygen demand.
Interestingly, the levels of V̇O2 relative to V̇O2max and the highest heart rate relative to maximal heart rate clearly showed that multiple sets of resistance exercise could be considered as vigorous- or high-intensity cardiovascular activity20,21,22. When viewed from an intensity perspective, squat exercise can be classified as a form of vigorous- or high-intensity activity22. However, since vigorous- or high-intensity aerobic activity is defined as an activity sustained for a prolonged period (e.g., ≥ 10 min)22, squat exercise does not meet this criterion given the rest interval periods and therefore may not be described as such. Furthermore, our findings suggest that aerobic demand of resistance exercise is much greater when individuals could exercise at a higher intensity without sacrificing the volume, represented as number of repetitions. Among the participants with high strength, V̇O2 exceeded their pre-determined V̇O2 max at the 4th set of squat exercise, while participants with low strength reached up to 91.69% of their V̇O2max at the 4th set. One noteworthy implication of our study is that we examined the fluctuations in cardiorespiratory responses and RPE throughout the progression of squatting repetitions and sets. This stands in contrast to merely assessing the average and peak V̇O2 observed during one bout (i.e., session) of squatting.
During rest intervals, we observed higher CO2 production than VO2 consumption, whereas the opposite was observed during the squat exercise periods. Typically, individuals only breathe once at each descending and ascending motion within a repetition during squat exercise, resulting in this distinctive breathing pattern that may cause a difference between pulmonary and cellular metabolic demands. During squatting exercises, participants may not be able to exhale sufficient amounts of CO2 produced as a result of bicarbonate buffering process. Breathing is modulated by central and peripheral chemoreceptors, which may respond to CO2 and H+23,24. Although elevations in CO2 and H+ during squat exercise are the primary precursors to an increase in breathing, breathing is limited to the exercise rhythm during squatting, which may cause hypercapnic acidosis24,25. When breathing was no longer limited to the exercise rhythm during rest intervals, participants hyperventilated and exhaled CO2. The increase in V̇CO2 in relation to V̇O2 was significant. While we did not measure the partial pressure of arterial CO2, our results indicated that participants experienced hypercapnia during the five sets of squat exercise. This was demonstrated by the ventilatory efficiency (Supplemental Fig. 2), which showed a continuous increase with successive sets. Diverse breathing techniques employed during squatting may yield varying V̇O2 and V̇CO2 responses.
It is unclear whether training proficiency and subsequent muscular strength are determinants of cardiorespiratory fitness26,27,28,29. Highly trained individuals are accustomed to a higher training intensity and frequency than relatively less-trained individuals, leading to greater neuromuscular output and adaptation30. As such, highly trained individuals can perform a greater volume (load, repetitions, intensity) of squat exercises, which may result in a higher level of V̇O2 than those with low strength during resistance exercise. Interestingly, we observed that the high strength group showed a higher level of V̇O2 (relative; normalized to body weight) at the same relative intensity compared with the low strength group. These results suggest that aerobic demand of resistance exercise may be more evident among individuals with certain levels of resistance training status. In addition, the predetermined V̇O2max level was lower in the high strength group compared to the low strength group, although this difference was not statistically significant. Furthermore, it is crucial to note that all study participants performed the squat exercise at 65% of their individual 1RM. This indicated that the squat load was obviously higher in the high strength group compared to the load used by the low strength group. Therefore, the high strength group may exhibit higher V̇O2 responses compared to the low strength group due to relatively lower aerobic efficiency and/or the absolute training load during exercise in the high strength group. Individuals, who are not accustomed to resistance exercise, may not have the same cardiorespiratory response as observed in our study.
The effort inherent to the execution of squatting exercises at 65% of 1RM, as performed in our study, is submaximal. This relative intensity corresponds to a margin of repetitions that is less than maximal exertion, influencing the V̇O2 observed. Previous research11,31 has established a relationship between the number of repetitions and selected percentages of one repetition maximum in both trained and untrained men. These studies11,31 indicate that the effort required at 65% of 1RM is substantial but not maximal, which aligns with our findings of significant oxygen demand during the exercise intervals. Our study further highlights that the substantial oxygen demand observed during the squatting exercise is influenced by both the training status of the participants and the submaximal nature of the effort. The high strength group demonstrated a higher V̇O2 relative to their V̇O2max compared to the low strength group. This suggests that individuals with higher strength capacity may be able to sustain higher aerobic demands during resistance exercises, even at submaximal intensities.
This study has several limitations. First, the findings of this study are specific to the squat exercise protocol used and cannot be generalized to other resistance exercise protocols, such as chest presses or arm curls. Different volumes (i.e., intensity, repetition, and training load) of squat exercises may result in different outcomes11. Second, nutritional and hydration intakes, which may be potential confounders, were not controlled for in this study. These factors may have impacted the association between squatting and cardiorespiratory outcomes. Lastly, our findings may not be generalizable to wider populations, given that we examined young, healthy, well-trained, male participants only.
Format: Would you prefer wearing a ring or a wrist-based device? If you want something understated that you can wear all the time and don’t mind not having a screen to glance at, then a ring would be ideal. If having a watch on your wrist is comfortable, then a smartwatch or wrist-based tracker may be the right choice.
Compatibility: If you’re an Apple user, ensure your fitness tracker is compatible with iOS. The same goes if you’re an Android user.
Storage capacity: For those who don’t want their fitness tracker to be dependent on their phone, look at a device with its own storage capacity.
Special features: Before purchasing a fitness tracker, consider the health metrics that are important to you for your favorite workouts. If you’d like your tracker to do more than monitor your fitness, you’ll be better off with a smartwatch like the Pixel Watch 4 or Apple Watch SE 3.
Wi-Fi or Bluetooth: If you’re the type of person who likes to leave their phone behind when working out but still needs internet access, ensure your fitness tracker has Wi-Fi.
GPS? For those who run, hike or walk and want to keep track of metrics like distance and pace without their phone, choose a fitness tracker that has built-in GPS.
Screen size: Once you decide you want a fitness tracker with a screen, make sure it fits your personal preferences. A smaller screen may be better if you prefer for it to be less obvious that you’re wearing a fitness tracker on your wrist.
Battery life: How often do you want to be charging your fitness tracker? If frequently charging your devices is a pet peeve, ensure your fitness tracker of choice has a long battery life, especially for your preferred workouts.
Water resistance: Individuals who work out by swimming or those who enjoy taking a dip in the pool after exercising will want a fitness tracker that is water-resistant. Confirm your device is rated for the depth you plan to swim at.
Subscription cost: It’s common for fitness trackers to come with the added cost of a subscription, particularly if you want to access all available features or require extra features for your workout or fitness goals. To guarantee that a fitness tracker is in your budget, check not only the price of the device, but also how much your subscription of choice will run you over the course of a year.
“This study suggests that when you exercise may matter, not just how much you exercise,” says senior study author Prashant Rao, MBBS, a sports cardiologist and physician-scientist at Beth Israel Deaconess Medical Center and Harvard Medical School, both in Boston.
The research, which will be presented at the American College of Cardiology’s Annual Scientific Session later this month, relied on minute-level heart rate data from nearly 15,000 adults. Dr. Rao says this allowed his team to capture long-term, real-world exercise data with much more detail and accuracy.
Early Morning Workouts Are Linked to Better Cardiometabolic Health
The study analyzed health records and Fitbit heart rate data collected over a year. Researchers identified periods when participants had an elevated heart rate for 15 minutes or more to track physical activity. Then they grouped participants into categories based on the time of day exercise occurred.
Researchers compared these timing groups with health data including rates of high blood pressure, obesity, high cholesterol, atrial fibrillation, coronary artery disease, and other cardiovascular health problems. They adjusted the findings to account for differences in age, sex, income level, total activity level, sleep, alcohol use, and smoking status.
The results showed that compared with adults who exercised later in the day, those who worked out in the morning were:
These risk reductions were independent of how much exercise people actually got. Adults who exercised between 7 and 8 a.m. had the lowest odds of coronary artery disease.
Aubrey Grant, MD, a sports cardiologist at MedStar Health in Washington, D.C., who wasn’t involved with the research, says the results suggest that “timing may be a previously underappreciated lever in cardiometabolic risk reduction.”
He adds that wearable technology is giving scientists more granular exercise data, which “opens a more nuanced conversation about how physical activity interacts with the body’s daily rhythms.”
Exercise Timing Is a ‘New Frontier’
A main limitation of the research is that it’s an observational study, “so we can’t establish causality,” Rao says. Because participants weren’t randomized to exercise at different times, the results only show a link, not that earlier exercise directly leads to the observed health benefits.
“While we did our best to adjust for confounders [factors that could muddy the results], timing may still reflect differences in work schedules, socioeconomic factors, or lifestyle patterns that aren’t potentially fully captured in our analyses,” he says.
The link between exercise timing and health is a “new frontier in exercise science,” says Dr. Grant. For decades, research has focused on “how much and how hard” people worked out — variables that still matter, he says.
Why Exercise Timing May Lower Cardiometabolic Risk
“The honest answer is that we do not fully know yet” why this link is appearing, Grant says.
“Morning exercise may align better with circadian physiology,” or how bodily functions naturally correspond to the time of day, he says. “Cortisol peaks early in the day and can prime the body for physical exertion, potentially enhancing metabolic efficiency,” Grant adds.
Exercise is also a natural stimulant. When you work out early, it revs up your bodily systems and energizes you for the day, says Andrew Freeman, MD, director of cardiovascular prevention and wellness at National Jewish Health in Denver. Dr. Freeman was not involved with the new study.
People who work out earlier may also have healthier lifestyle habits, overall, says Alex Rothstein, EdD, an assistant professor of exercise science at the New York Institute of Technology in Old Westbury.
“If you work out earlier in the day, you tend to have fewer excuses to not work out,” and you may exercise more consistently, says Dr. Rothstein, who was not involved with the new research.
Should You Start Exercising in the Morning?
Freeman recommends getting 30 minutes a day of “breathless physical activity,” including a combination of cardio and strength training. But if you prefer to work out in the afternoons or have responsibilities preventing you from exercising in the morning, don’t worry.
“It does not mean people should feel guilty about evening workouts,” Grant says. “It means that when we counsel patients on optimizing their health, exercise timing is now a legitimate part of that conversation, alongside sleep, nutrition, and stress management.”
If you have flexibility, though, Rothstein suggests exercising in the morning, as it’s less likely that something will interfere with your workout later on, and it may offer extra heart health benefits.
“The most important message is still: Exercise consistently, regardless of timing,” Rao says. However, “Timing may represent a simple, low-cost way to potentially optimize health.”
Fitness
The HFA Show 2026 Demonstrates the Power of Community With Strong Turnout and Programming – Health & Fitness Association
From the HFA Hall of Fame to Innovation Alley to the launch of new products from more than 60 companies, The HFA Show 2026 delivers a standout week.
The 2026 HFA Hall of Fame inductees pose together (left to right): Cirulli, Eschbach, Landers, Mills, Runyon, and Elaine LaLanne. Missing are Dave Mortensen, who could not attend, and Jack LaLanne, who received the award posthumously. In the second photo, Keith Morrison, a correspondent for Dateline NBC, presents Elaine LaLanne as an inductee.
The HFA Show 2026 recorded 10,300 registrants, 380 exhibitors, 52 sponsors, and 150 speakers for the March 16-18 event in San Diego, according to the Health & Fitness Association (HFA). It was also the launching pad for new products and services from more than 60 companies.
“What an incredible week full of high energy, dynamic networking, insightful learning, and new product discoveries,” said HFA President and CEO Liz Clark. “It was gratifying to support such an extraordinary group of industry leaders and innovators from around the world with this year’s show. Our team has poured more than a year of work into this event, and we’re already energized to make next year’s gathering in Las Vegas on March 10–12, 2027, even more spectacular.”
Clark went on to thank additional groups beyond HFA team members.
“We’d like to thank all our sponsors, exhibitors, speakers, and board members for making this year’s event such a strong and inspiring showcase for the industry,” Clark said. “Your commitment and partnership helped create a world-class experience that truly moved our industry forward.”
The unofficial launch of the event occurred on the evening of March 15, with 240 people gathering for the HFA Hall of Fame Induction Ceremony, sponsored by The Bay Club Company, to honor the organization’s second class of inductees: Gainesville Health & Fitness CEO Joe Cirulli, Exhale and ResetOne Founder Annbeth Eschbach, Fitness Formula Founder Gale Landers, Les Mills Founder and Managing Director Phillip Mills, Purpose Brands Co-founders Dave Mortensen and Chuck Runyon, and fitness icons Jack and Elaine LaLanne. Ticket sales and sponsorships for the HFA Hall of Fame ceremony raised more than $200,000 for the HFA Foundation, a 501(c)3 public charity that works to support health through exercise.
The evening also included a celebration recognizing Elaine LaLanne’s 100th birthday, which was March 19. Keith Morrison, a Dateline NBC correspondent and friend of Elaine, presented Elaine and her husband Jack, who passed away in 2011, for induction. Celebrities such as Billy Crystal, Mark Wahlberg, and Tony Danza sent videos congratulating her on her 100th birthday.
HFA handed out three other awards at the event. The Jim Worthington Advocate of the Year Award went to Chris Craytor, CEO of ACAC Fitness & Wellness Centers, for his service to the fitness industry and HFA. The John Holsinger Global Leader Award was given to LifeFit Group CEO Martin Seibold. Bodytech Colombia Co-founder and Executive Vice President Gigliola Aycardi received the Woman Leader Award in Honor of Julie Main.
This year’s keynoters (left to right): Dhawan, Itzler, and Ohno.
The HFA Show included annual President’s Address by Clark as well as three keynote addresses:
- March 16 – Clark recapped the highlights of the past year for HFA and urged even further engagement by industry leaders as global influence and expectations grow for the industry.
- March 16 – Author and teamwork expert Erica Dhawan shared strategies for building trust, fostering agility, and strengthening collaboration in the age of AI. Her keynote was sponsored by Zenoti.
- March 17 – Author and entrepreneur Jesse Itzler shared lessons about creating opportunity, cultivating resilience, and building a life that achieves big goals without sacrificing what matters most. His keynote was sponsored by Matrix.
- March 18 – Olympic speed-skating champion Apolo Ohno shared lessons on reinvention, adaptability, and performance in a rapidly changing environment in his keynote, sponsored by ROR.
Other highlights of the conference program were:
- The 29th Annual Financial Panel, which was renamed the Rick Caro Financial Panel in honor of Rick Caro, president of Management Vision, who created the panel 28 years ago and had moderated it each year until his death in August 2025. This year’s panel was sponsored by AltaDX.
- The Women’s Leadership Summit and Reception, sponsored by Daxko.
- The Brazilian Forum and the Latin American Forum, both sponsored by ABC Fitness.
- The Canadian Forum, EMEA Forum, and APAC Forum
Highlights of the trade show floor were:
- Innovation Alley (sponsored by Sweatworks) featurinh the following companies: Alchemy Innovations LLC, AI Advertising by Mixo Ads, BELLIX, Bolt Recovery, Buzz Bomb Caffeine Company, DetecFit, Fit – M.O., Fit-X, HipDoc, InSquare, MatFresher, Milton AI, Nervō Labs, ObliQ Fitness, OmniFit, OnSight, Silient, Superset App, and xplate.
- Innovation Alley Pitchfest, which featured many of the Innovation Alley companies offering a three-minute pitch of their product. The winners of the Pitchfest will be announced soon. They will receive a complimentary booth at The HFA Show 2027 and will be recognized in a future issue of Health & Fitness Business.
- The New Product Zone featuring nine companies: Body Energy Technology, Buzz Bomb Caffeine, Core Champion, Echelon Fit, Escape Fitness, Linear Bar, Martoni Bikes, The Abs Company, and WeGym
- The Pickleball Experience
- The Demonstration Stage
- The Recovery Lounge (outside the trade show floor) with products from Am-Finn Sauna Company, CryoBuilt, Silent, WellFit, and WellnessSpace Brands.
“What stood out this year wasn’t just the scale of the event, but the strength of the conversations happening across every part of the show,” Clark said. “From the keynote stage and education sessions to the trade show floor, industry leaders came together to share ideas, explore innovation, and build the relationships that will help shape the future of health and fitness.”
HFA would like to acknowledge Alloy Personal Training Solutions, LLC for authorizing the use of its registered trademark “Stronger Together” as the theme for The HFA Show 2026. The HFA Show 2027 will take place March 10-12, 2027, at Mandalay Bay in Las Vegas.
Kansas firefighters rescue chubby cat trapped in massive recliner while trying to hide from the vet
Will Louisiana’s U.S. Senate candidates debate? Bill Cassidy says no to Moon Griffon.
Maine Senate advances ‘right to repair’ electronics bill
‘Mattresses all over the place’: Maryland begins yearly operation to clean state highways – WTOP News
Showers, thunderstorms expected to hit SE Michigan Thursday — What to know
Florida High School Football Rankings: Top 25 teams – Oct. 21
How old is Bo Nix? What to know about Oregon quarterback ahead of 2024 NFL Draft
Cleary's 21 help Le Moyne down Central Connecticut State 69-64 in OT
99th annual Pony Swim held in Virginia
Indiana Members Credit Union announced as new anchor tenant at Bottleworks District
LaGuardia Crash Timeline: Moments Before Air Canada Plane Collided With Fire Truck
Chicago alderwoman apologizes for ‘wrong place at the wrong time’ comment on slain student
Fake Euronews website targets Hungary election with false claims
An air traffic controller was juggling extra roles during the LaGuardia plane crash
Iran War: Pentagon set to send thousands of elite 82nd Airborne troops to region | BBC News
-
Detroit, MI6 days agoDrummer Brian Pastoria, longtime Detroit music advocate, dies at 68
-
Georgia1 week agoHow ICE plans for a detention warehouse pushed a Georgia town to fight back | CNN Politics
-
Movie Reviews6 days ago‘Youth’ Twitter review: Ken Karunaas impresses audiences; Suraj Venjaramoodu adds charm; music wins praise | – The Times of India
-
Education1 week agoVideo: Turning Point USA Clubs Expand to High Schools Across America
-
Sports4 days agoIOC addresses execution of 19-year-old Iranian wrestler Saleh Mohammadi
-
Science1 week agoIndustrial chemicals have reached the middle of the oceans, new study shows
-
Science1 week agoHow a Melting Glacier in Antarctica Could Affect Tens of Millions Around the Globe
-
Culture1 week agoTest Your Memory of Great Lines From Classic Irish Poems