
If you’ve ever wondered what separates elite endurance athletes from weekend warriors—or why your friend can cruise up hills while you’re gasping for air—the answer often comes down to a vital sign you’ve probably never heard of — VO2 max. Think of it as your cardiovascular system’s horsepower rating, a number that tells you how efficiently your body can use oxygen during intense exercise.
What VO2 Max Actually Means
VO2 max stands for maximal oxygen consumption; it measures the maximum amount of oxygen your body can take in, transport, and use during exercise. Scientists express it in milliliters of oxygen per kilogram of body weight per minute (ml/kg/min). When you’re working out at your absolute limit—say, sprinting up a hill until you simply can’t go any faster—your muscles are burning through oxygen to produce energy. VO2 max represents the ceiling of that process, the point where your body has maxed out its oxygen delivery system and can’t use any more oxygen even if you try to push harder.
An average sedentary man might have a VO2 max around 30-40 ml/kg/min, while an average woman might measure 25-30 ml/kg/min. Elite endurance athletes, however, occupy an entirely different universe. Cross-country skiers and distance runners can reach values of 70-85 ml/kg/min or even higher. The legendary Norwegian cyclist Oskar Svendsen reportedly recorded a VO2 max of 97.5 ml/kg/min, which is probably the upper reaches of human cardiovascular capacity.
The rest of us are also affected by VO2 Max. In later life, it is closely tied to our everyday activities. There’s a minimum aerobic capacity required for independent living—walking briskly, climbing stairs, carrying groceries. As VO2 max declines to that functional threshold, small losses can translate into disproportionate declines in independence. Conversely, modest improvements can produce meaningful gains in stamina, balance, and confidence.
The Gold Standard of Measurement
The most accurate way to measure VO2 max involves what’s called a graded exercise test, typically performed in a lab or clinical setting. You’ll hop on a treadmill or stationary bike while wearing a mask connected to a metabolic cart—essentially a sophisticated machine that analyzes every breath you take. The test starts easy but gets progressively harder every few minutes. The technician increases either the speed, incline, or resistance while the equipment measures exactly how much oxygen you’re consuming and how much carbon dioxide you’re producing.
You keep going until you reach exhaustion—the point where you literally cannot continue despite maximum effort. The highest oxygen consumption rate recorded during this test is your VO2 max. It’s not a particularly pleasant experience, but it’s incredibly accurate. The test also provides valuable data about your anaerobic threshold, the point where your body starts relying more heavily on systems that don’t require oxygen and where lactic acid begins accumulating in your muscles.
For those of us without access to exercise labs, there are several field tests we can use to estimate VO2 max reasonably well. The Cooper test, developed by Dr. Kenneth Cooper in the 1960s, involves running as far as you can in 12 minutes on a track (that wouldn’t be too far for me). The distance you cover correlates with your VO2 max through established formulas [VO2max: (distance covered in meters – 504.9) / 44.73 = VO2 max in ml/kg/min]. Age and gender normed values can be found on a number of fitness websites. Many fitness watches and apps now offer VO2 max estimates based on heart rate data during runs, though these are less precise than laboratory testing.
Why This Number Matters
VO2 max serves as one of our strongest predictors of cardiovascular health and longevity. Research published in major medical journals has consistently shown that higher VO2 max values correlate with lower risks of heart disease, diabetes, and all-cause mortality. A 2018 study in the Journal of the American Medical Association (JAMA) that followed over 122,000 patients found that cardiorespiratory fitness (measured by VO2 max) was a better predictor of mortality than traditional risk factors like hypertension, diabetes, or even smoking.
The relationship is striking, for every 3.5 ml/kg/min increase in VO2 max, mortality risk drops by about 13 percent. People in the lowest fitness category (those with the poorest VO2 max scores) have death rates two to three times higher than those in the highest fitness category, even when controlling for other health factors.
Beyond mortality statistics, VO2 max influences your daily quality of life. A higher VO2 max means your heart doesn’t have to work as hard during routine activities. Climbing stairs, carrying groceries, playing with kids or grandkids—all these activities demand less relative effort when your cardiovascular system operates efficiently. Your body becomes better at delivering oxygen-rich blood to working muscles and clearing away metabolic waste products, which means you fatigue less easily and recover more quickly.
The Path to Improvement
The encouraging news is that VO2 max responds remarkably well to training, especially if you’re starting from a sedentary baseline. You can’t completely escape genetics—some people are simply born with larger hearts, more efficient lungs, or a higher percentage of slow-twitch muscle fibers—but training can typically improve VO2 max by 15-30 percent in previously untrained people.
The most effective approach combines several training methods. High-intensity interval training (HIIT) has emerged as particularly powerful tool for boosting VO2 max. These workouts involve short bursts of near-maximal effort followed by recovery periods. A classic protocol might involve running hard for four minutes at about 90-95 percent of your maximum heart rate, then recovering with light jogging for three minutes, repeated four or five times. Studies show that just two or three HIIT sessions per week can produce significant improvements in VO2 max within eight to twelve weeks.
Longer, steady-state aerobic exercise also plays a crucial role. These sessions—think longer runs at a conversational pace—improve your cardiovascular system’s efficiency and build the capillary networks that deliver oxygen to muscles. The optimal training program typically includes both high-intensity intervals and longer moderate-intensity sessions, along with adequate recovery time.
Interestingly, resistance training can indirectly support VO2 max improvements as well. While lifting weights won’t directly boost your oxygen consumption capacity the way running does, it helps maintain lean muscle mass, improves movement efficiency, and can enhance your ability to perform high-intensity cardiovascular work.
This high intensity training is all well and good for young, relatively healthy people. But what about older folks, particularly those with underlying medical problems?
The encouraging news: VO2 max responds to training well into our 70s, 80s, and beyond. Key approaches involve the same elements but tailored to age and medical history.
Moderate-intensity aerobic exercise (brisk walking, cycling, swimming) performed most days of the week is the primary element. Individually adjusted interval training, including carefully supervised higher intensity intervals, have shown impressive VO2 max gains even in older populations. Strength training is beneficial for older folks as well, and as an added benefit, it helps maintain and even improve bone density. A personal trainer can help design your fitness program to maximize improvement while minimizing the likelihood of injury.
Stop any exercise immediately if you experience chest pain, dizziness, or extreme shortness of breath. Remember consistency matters more than intensity alone and, most importantly, never start any exercise program without checking with your doctor first.
The Inevitable Decline
Here’s the less cheerful part: VO2 max naturally declines with age, typically dropping about 10 percent per decade after age 30 in sedentary people. This decline accelerates after age 70. However—and this is crucial—regular exercise dramatically slows this process. Senior athletes who maintain consistent training can preserve VO2 max values that rival or exceed those of sedentary people decades younger. A fit 60-year-old can easily have a higher VO2 max than an inactive 40-year-old.
The decline happens for several reasons: maximum heart rate decreases, cardiac output drops, muscle mass decreases, and the body becomes less efficient at extracting oxygen from blood. But none of these changes are inevitable consequences of aging alone—they’re heavily influenced by activity levels.
Putting It in Perspective
While VO2 max provides valuable information about cardiovascular fitness, it’s worth remembering that it’s just one metric among many. You don’t need the VO2 max of an Olympic athlete to be healthy and enjoy an active life (thankfully). A moderate VO2 max maintained consistently into your later years will serve you far better than a high value in your twenties followed by decades of inactivity.
The real value of understanding VO2 max lies in what it represents: your body’s fundamental capacity to generate energy and support movement. When you work to improve this capacity through regular cardiovascular exercise, you’re investing in both your current quality of life and your long-term health prospects. Every little bit helps—so put down the remote, get up off the couch and start walking. You’ll be glad you did.
Sources:
- American College of Sports Medicine on VO2 max testing: https://www.acsm.org/
- Mayo Clinic on cardiorespiratory fitness: https://www.mayoclinic.org/
- National Institutes of Health research on fitness and mortality: https://www.nih.gov/
- JAMA Network 2018 study on cardiorespiratory fitness and mortality: https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2707428
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When They Knew: How the Fossil Fuel Industry Buried Its Own Climate Science
By John Turley
On February 9, 2026
In Commentary, Politics
The story begins not with climate deniers casting doubt on new science, but with something far more troubling: companies conducting rigorous research, understanding exactly what their products would do to the planet, and then spending decades lying to the public. They treated science as an internal planning tool and then deployed public relations, front groups, and “manufactured doubt” to delay regulation and protect profits.
The Oil Industry’s Own Scientists Saw It Coming
In 1977, a scientist named James Black stood before Exxon’s management committee with an uncomfortable message. According to internal documents later uncovered by investigative journalists, Black told executives that burning fossil fuels was increasing atmospheric carbon dioxide, and that continually rising CO2 levels would increase global temperatures by two to three degrees—a projection that is still consistent with today’s scientific consensus. He warned that we had a window of just five to ten years before “hard decisions regarding changes in energy strategies might become critical”.
What happened next is remarkable for its precision. Throughout the late 1970s and 1980s, Exxon assembled what one scientist called “a credible scientific team” to investigate the climate question. They launched ambitious projects, including outfitting a supertanker with custom instruments to measure how oceans absorbed CO2—one of the most pressing scientific questions of the era. A 2023 Harvard study analyzing Exxon’s internal climate projections from 1977 to 2003 found they predicted global warming with what researchers called “shocking skill and accuracy.” Specifically, the company projected 0.20 degrees Centigrade of warming per decade, with a margin of error of just 0.04 degrees—a forecast that has proven largely correct.
Exxon wasn’t alone. Shell produced a confidential 1988 report titled “The Greenhouse Effect” that warned of climate changes “larger than any that have occurred over the last 12,000 years,” including destructive floods and mass migrations. The report revealed Shell had been running an internal climate science program since 1981. In one striking document from 1986, Shell predicted that fossil fuel emissions would cause changes “the greatest in recorded history”.
Even industry groups understood what was coming. In 1980, the American Petroleum Institute (API) invited Stanford scientist John Laurmann to brief oil company representatives at its secret “CO2 and Climate Task Force”. His presentation, now public, warned that continued fossil fuel use would be “barely noticeable” by 2005 but by the 2060s would have “globally catastrophic effects.” That same year, the API called on governments to triple coal production worldwide, publicly insisting there would be no negative consequences.
The Coal Industry Knew Even Earlier
If anything, the coal industry understood the problem first. A 1966 article in the trade publication Mining Congress Journal by James Garvey, president of Bituminous Coal Research Inc., explicitly discussed how continued coal consumption would increase atmospheric temperatures and cause “vast changes in the climates of the earth.” A combustion engineer from Peabody Coal, now the world’s largest coal company, acknowledged in the same publication that the industry was “buying time” before air pollution regulations would force action.
This 1966 evidence is particularly damning because it predates widespread public awareness by decades. The coal industry didn’t stumble into climate denial—they entered it with full knowledge of what they were obscuring.
Major coal interests also had early awareness that carbon emissions posed regulatory and market risks, particularly for coal‑fired electricity, and they participated in joint industry research and strategy discussions about climate change in the 1980s and 1990s. At the same time, coal associations helped create public campaigns such as the Information Council for the Environment (ICE—even then a disturbing acronym), whose internal planning documents explicitly set an objective to “reposition global warming as theory (not fact)” and to target specific demographic groups with tailored doubt‑based messages.
According to a report from the Union of Concerned Scientists, these efforts often relied on “grassroots” fronts, advertising, and even forged constituent letters to legislators to undermine support for climate policy and to counter the conclusions of mainstream climate science, which even the companies’ own experts did not refute.
What They Said Publicly
The contrast between private knowledge and public statements is stark. While Exxon scientists were building sophisticated climate models internally, the company’s public messaging emphasized uncertainty. In a 1997 speech, Exxon CEO Lee Raymond told an audience at the World Petroleum Conference: “Let’s agree there’s a lot we really don’t know about how climate change will change in the 21st century and beyond”. They spread messaging that emphasized uncertainty, framed global warming as just a “theory,” and highlighted supposed flaws in climate models, even as their own scientists were using those models to make precise projections. The company and allied trade associations supported think tanks and advocacy groups such as Citizens For Sound Science, that questioned if human activity was responsible for warming and opposed binding limits on emissions, producing a stark discrepancy between internal scientific knowledge and external communication.
In 1989, Exxon helped create the Global Climate Coalition—despite its environmental sounding name, the organization worked to cast doubt on climate science and block clean energy legislation throughout the 1990s. Electric utilities and coal‑linked organizations joined this coalition to systematically attack climate scientists and lobby to weaken or stall international agreements like the Kyoto Protocol, despite internal recognition that greenhouse gases were driving warming.
Internal API documents from a 1998 meeting reveal an explicit strategy to “ensure that a majority of the American public… recognizes that significant uncertainties exist in climate science”.
In 1991, Shell produced a film, “Climate of Concern,” which stated that human driven—as opposed to greenhouse gas driven—climate change was happening “at a rate faster than at any time since the end of the ice age” and warned of extreme weather, flooding, famine, and climate refugees. They understood the science but tried to shift the blame.
According to a 2013 Drexel University study, between 2003 and 2010 alone, approximately $558 million was distributed to about 100 climate change denial organizations. Greenpeace reports that Exxon alone spent more than $30 million on think tanks promoting climate denial.
The Tobacco Playbook
The parallels to Big Tobacco’s strategy are not coincidental—they’re intentional. Research by the Center for International Environmental Law uncovered more than 100 documents from the Tobacco Industry Archives showing that oil and tobacco companies not only used the same PR firms and research institutes, but often the same individual researchers. The connection goes back to at least the 1950s. A report published in Scientific American suggests the oil and tobacco industries both hired the PR firm Hill & Knowlton Inc. as early as 1956.
A 1969 internal memo from R.J. Reynolds Tobacco Company stated plainly: “Doubt is our product since it is the best means of competing with the ‘body of fact’ that exists in the mind of the general public”. This became the template. Create uncertainty. Emphasize what isn’t known rather than what is. Fund research that casts doubt. Attack the credibility of independent scientists. They formed organizations with scientific-sounding names that existed primarily to muddy the waters.
In one particularly brazen example, a 2015 presentation by Cloud Peak Energy executive Richard Reavey titled “Survival Is Victory: Lessons From the Tobacco Wars,” explicitly coached coal executives on how to apply tobacco industry tactics.
What makes the fossil fuel case particularly egregious is the temporal dimension. These weren’t companies caught off-guard by emerging science. They funded the research. They understood the findings. Their own scientists urged action. A 1978 Exxon memo noted this could be “the kind of opportunity we are looking for to have Exxon technology, management and leadership resources put into the context of a project aimed at benefitting mankind”.
Instead, when oil prices collapsed in the mid-1980s, Exxon pivoted from conducting climate research to funding climate denial. By the late 1980s, according to reporting by InsideClimate News, Exxon “curtailed its carbon dioxide research” and “worked instead at the forefront of climate denial”.
Where We Stand Now
Across the oil, gas, and coal industries, there is not a genuine scientific dispute inside companies but a divergence between what in‑house experts knew and what corporate leaders chose to communicate to the public and policymakers. This divergence mirrors the tobacco industry’s long‑running use of organized doubt. In both arenas, industry actors treated early recognition of harm as a legal and political threat and responded by investing in campaigns to confuse, delay, and reframe the science rather than addressing the risks their own research had identified.
The evidence trail has led to legal action. More than 20 cities, counties, and states have filed lawsuits against fossil fuel companies for damages caused by climate change, arguing the industry knowingly deceived the public. The European Parliament held hearings in 2019 on climate denial by ExxonMobil and other actors. The hashtags #ExxonKnew, #ShellKnew, and #TotalKnew have become rallying cries for accountability.
Senator Sheldon Whitehouse has explicitly compared the fossil fuel industry’s actions to the tobacco racketeering case that ultimately held cigarette makers accountable. As he noted in a Senate speech, the elements of a civil racketeering case are straightforward: defendants conducted an enterprise with a pattern of racketeering activity.
The difference between the tobacco and fossil fuel cases may be one of scale. As researchers Naomi Oreskes and Erik Conway documented in their book Merchants of Doubt, both industries worked to obscure truth for profit. But while tobacco kills individuals, climate change threatens entire ecosystems and future generations. The time to act is now.
Sources:
Scientific American – “Exxon Knew about Climate Change Almost 40 Years Ago”
https://www.scientificamerican.com/article/exxon-knew-about-climate-change-almost-40-years-ago/
Harvard Gazette – Harvard-led analysis finds ExxonMobil internal research accurately predicted climate change
https://news.harvard.edu/gazette/story/2023/01/harvard-led-analysis-finds-exxonmobil-internal-research-accurately-predicted-climate-change/
InsideClimate News – Exxon’s Own Research Confirmed Fossil Fuels’ Role in Global Warming Decades Ago
https://insideclimatenews.org/news/02052024/from-the-archive-exxon-research-global-warming/
PBS Frontline – Investigation Finds Exxon Ignored Its Own Early Climate Change Warnings
https://www.pbs.org/wgbh/frontline/article/investigation-finds-exxon-ignored-its-own-early-climate-change-warnings/
NPR – Exxon climate predictions were accurate decades ago. Still it sowed doubt
https://www.npr.org/2023/01/12/1148376084/exxon-climate-predictions-were-accurate-decades-ago-still-it-sowed-doubt
Science (journal) – Assessing ExxonMobil’s global warming projections
https://www.science.org/doi/10.1126/science.abk0063
Climate Investigations Center – Shell Climate Documents
https://climateinvestigations.org/shell-oil-climate-documents/
The Conversation – What Big Oil knew about climate change, in its own words
https://theconversation.com/what-big-oil-knew-about-climate-change-in-its-own-words-170642
ScienceAlert – The Coal Industry Was Well Aware of Climate Change Predictions Over 50 Years Ago
https://www.sciencealert.com/coal-industry-knew-about-climate-change-in-the-60s-damning-revelations-show
The Intercept – A Major Coal Company Went Bust. Its Bankruptcy Filing Shows That It Was Funding Climate Change Denialism
https://theintercept.com/2019/05/16/coal-industry-climate-change-denial-cloud-peak-energy/
Center for International Environmental Law – Big Oil Denial Playbook Revealed by New Documents
https://www.ciel.org/news/oil-tobacco-denial-playbook/
Wikipedia – Tobacco industry playbook
https://en.wikipedia.org/wiki/Tobacco_industry_playbook
Scientific American – Tobacco and Oil Industries Used Same Researchers to Sway Public
https://www.scientificamerican.com/article/tobacco-and-oil-industries-used-same-researchers-to-sway-public1/
Environmental Health (journal) – The science of spin: targeted strategies to manufacture doubt with detrimental effects on environmental and public health
https://link.springer.com/article/10.1186/s12940-021-00723-0
Senator Sheldon Whitehouse – Time to Wake Up: Climate Denial Recalls Tobacco Racketeering
https://www.whitehouse.senate.gov/news/speeches/time-to-wake-up-climate-denial-recalls-tobacco-racketeering/
VICE News – Meet the ‘Merchants of Doubt’ Who Sow Confusion about Tobacco Smoke and Climate Change
https://www.vice.com/en/article/meet-the-merchants-of-doubt-who-sow-confusion-about-tobacco-smoke-and-climate-change/
Union of Concerned Scientists – The Climate Deception Dossiers
https://www.ucs.org/sites/default/files/attach/2015/07/The-Climate-Deception-Dossiers.pdf
Illustration generated by author using ChatGPT.