Global Warming May Dwindle the Supply of a Key Brain Nutrient
By Bret Stetka
Glaciers continue to melt. Sea levels are on the rise. And now scientists believe the changing climate may put our brains at risk. A new analysis predicts that by 2100, increasing water temperatures brought on by a warming planet could result in 96 percent of the world's population not having access to an omega-3 fatty acid crucial to brain health and function.
That molecule is called docosahexaenoic acid, or DHA. It is the most common fatty acid in the mammalian brain and plays a key role in the survival and function of our neural cells, especially during the organ's development. Data suggest that not having enough of the compound may increase the risk of conditions such as depression and attention deficit hyperactivity disorder and impair cognition in people with early dementia.
Our bodies do not make much DHA, so, for the most part, we obtain it through diet. Plants and meats have modest amounts of the fatty acid, but the most abundant source by far is fish (or fish-derived supplements). Fish obtain DHA by consuming algae. The authors of the new study predict that rising temperatures could disrupt algal DHA production and lead to a 10 to 58 percent reduction in availability of the compound, depending on the geographic region.
To predict the future of DHA availability, they used data from the Food and Agriculture Organization of the United Nations and the fishery research institute Sea around Us to get numbers on how much edible fish are caught and farmed worldwide each year and on how much of that maritime tonnage is composed of DHA-containing fat. Then, using data showing how temperature influences algal DHA production, the researchers determined roughly how much of the fatty acid is presently available by consuming fish per capita versus how much will be available 80 years from now.
Their predictions show that larger countries with rapid population growth in East and Southeast Asia — including China, Japan and Indonesia — will face the most severe DHA shortages. Most African countries — especially landlocked ones — will also end up falling below recommended DHA intake, whereas nations with small populations and active fishing industries, such as Norway, Chile and New Zealand, will likely maintain access to adequate omega-3s.
"I already had an idea that DHA would decrease, based on previous data," recalls Stefanie Colombo, an assistant professor in aquaculture nutrition at Dalhousie University and co-lead author on the new paper. "But I was surprised and concerned when we saw the decline in DHA per capita—that people in some areas of the world would be more affected."
Tom Brenna, a professor with joint appointments in pediatrics, chemistry and human nutrition at the University of Texas at Austin, points out that the new results are open to a range of interpretation: "The [predicted] interval of 10 to 58 percent is so large as to be the difference between a mild inconvenience and a calamity." Yet he welcomes any investigation into the global DHA supply.
Brenna, who was not involved in the new study, also points out that whether or not dietary DHA is necessary in adults has been an area of conflict for decades. Yet he and most experts in the field agree that it is a critical nutrient during brain development and even into the late teen years — and that its influence on brain function may vary, based on an individual's genetic profile.
Omega-3 fatty acids can be derived from terrestrial sources, including nuts, seeds and land animals. Yet as Michael Crawford, now at Imperial College London, discovered in the 1970s, "ready-made" DHA — such as found in fish — is incorporated into the developing brain with 10-fold greater efficiency than plant-sourced DHA.
Crawford is a pioneer in understanding the relationship between omega-3 fatty acids and brain health and believes that the evolution of our big and complex primate brain would have been impossible without access to DHA. He also thinks that a decline in consumption of omega-3s because of our increasingly processed diet explains increasing rates of mental illness and declining IQ. Marine agriculture such as projects now underway in Japan might be essential to saving ourselves and the planet. "If mental illness continues to escalate, then Homo sapiens are finished," Crawford predicts. "Seventy-one percent of the planet's surface is water, and marine cultivation will help reverse this trend. Without farming the seabed and oceans, food security goes out of the window."
Aquaculture initiatives abound throughout the world, including those intent on farming algae as a source of DHA. Other researchers are using genetic engineering to grow plants with a more available form of the fatty acid. And Richard P. Bazinet, a professor in the department of nutritional sciences at the University of Toronto and a co-author of the new paper, is working to understand how DHA enters the brain and how much of it a healthy adult brain actually needs.
Colombo is hopeful that in the face of a changing climate, scientists will devise new sources of DHA. And she plans to study how warming waters will affect fish metabolism and DHA availability. Yet she admits the outcome does not look good: "I don't think this is something we can ignore. In terms of the climate warming, we can't continue on this same trajectory."
Omega-3 fatty acids are essential fats that have numerous health benefits. This article takes a detailed look at the 3 most important types of omega-3shttps://t.co/I8K8jqZiUl— Frank Lipman MD (@DrFrankLipman) July 10, 2019
This story originally appeared in Scientific American. It is republished here as part of EcoWatch's partnership with Covering Climate Now, a global collaboration of more than 250 news outlets to strengthen coverage of the climate story.
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By Sara Lindberg
Whether you've hit a workout plateau or you're just ready to turn things up a notch, adding more strenuous exercise — also known as high-intensity exercise — to your overall fitness routine is one way to increase your calorie burn, improve your heart health, and boost your metabolism.
However, to do it safely and effectively, there are some guidelines you should follow. Keep reading to learn more about the benefits of vigorous exercise and how to safely dial up the intensity of your workouts.
What Is Considered Strenuous Exercise?<p>When it comes to exercise, the intensity of how hard you work out is just as important as the duration of your exercise session. In general, exercise intensity is divided into three categories:</p><ul><li>low</li><li>moderate</li><li>vigorous or strenuous</li></ul><p>For an activity to be vigorous, you need to work at 70 to 85 percent of your maximum heart rate, according to the<a href="https://www.heart.org/en/healthy-living/fitness/fitness-basics/target-heart-rates" target="_blank"> American Heart Association</a>. Examples of vigorous exercise include:</p><ul><li>running</li><li>cycling at 10 mph or faster</li><li>walking briskly uphill with a heavy backpack</li><li>jumping rope</li></ul><p>Low to moderate exercise is easier to sustain for longer periods since you work below 70 percent of your maximum heart rate and, sometimes, well below that level.</p><p>To reap health benefits, the <a href="https://www.hhs.gov/fitness/be-active/physical-activity-guidelines-for-americans/index.html" target="_blank">Physical Activity Guidelines for Americans</a> recommends that people age 18 and older get one of the following:</p><ul><li><strong>150 minutes</strong> of moderate-intensity aerobic activity per week</li><li><strong>75 minutes</strong> of vigorous aerobic activity per week</li><li><strong>combination of both types</strong> of activity spread throughout the week</li></ul>
Strenuous Exercise Vs. Moderate Exercise<p>Increasing your exercise intensity is fairly simple to do. You can still participate in your favorite activities — just at a more vigorous pace.</p><p>One of the benefits of more strenuous exercise is that you can reap the same rewards as moderate-intensity exercise but in less time. So, if time is of the essence, doing a more strenuous 20-minute workout can be just as beneficial as doing a slower 40-minute workout session.</p><p>Here are some examples of <a href="https://www.cdc.gov/nccdphp/dnpa/physical/pdf/pa_intensity_table_2_1.pdf" target="_blank">strenuous vs. moderate exercise<span></span></a>.</p><table><tbody><tr><th>Moderate intensity</th><th>Strenuous intensity</th></tr><tr><td>bicycling at less than 10 mph</td><td>bicycling at more than 10 mph</td></tr><tr><td>walking briskly</td><td>running, or hiking uphill at a steady pace</td></tr><tr><td>jog-walk intervals</td><td>water jogging/running</td></tr><tr><td>shooting baskets in basketball</td><td>playing a basketball game</td></tr><tr><td>playing doubles tennis</td><td>playing singles tennis</td></tr><tr><td>raking leaves or mowing the lawn</td><td>shoveling more than 10 lbs. per minute, digging ditches</td></tr><tr><td>walking stairs</td><td>running stairs</td></tr></tbody></table>
Benefits of Vigorous Exercise<p>Besides being more efficient, turning up the heat on your fitness sessions can benefit your health in a variety of ways. Let's take a closer look at some of the evidence-based benefits of a higher intensity workout.</p><ul><li><strong>Higher calorie burn.</strong> According to the <a href="https://www.acefitness.org/education-and-resources/professional/expert-articles/5008/7-things-to-know-about-excess-post-exercise-oxygen-consumption-epoc/?utm_source=Rakuten&utm_medium=10&ranMID=42334&ranEAID=TnL5HPStwNw&ranSiteID=TnL5HPStwNw-hYlKnAcfzfixAUsvnO6Ubw" target="_blank">American Council on Exercise</a>, working out at a higher intensity requires more oxygen, which burns more calories. It also contributes to excess post-exercise oxygen consumption (EPOC) or the "afterburn effect" that allows you to continue burning calories even after you finish working out. This means your metabolism will stay elevated for longer after a vigorous exercise session.</li><li><strong>More weight loss.</strong> A <a href="https://www.healthline.com/health-news/interval-workouts-will-help-you-lose-weight-more-quickly" target="_blank">higher calorie burn</a> and an elevated metabolism will help you lose weight more quickly than doing low- or moderate-intensity exercise.</li><li><strong>Improved heart health.</strong> According to a <a href="https://www.ncbi.nlm.nih.gov/pubmed/16377300" target="_blank">2012 study</a>, high- and moderate-intensity exercise appears to offer low chance of cardiovascular events, even in those with heart disease. Cardiovascular benefits may include improvements in:<ul><li><a href="https://www.healthline.com/health/diastole-vs-systole" target="_blank">diastolic blood pressure</a></li><li><a href="https://www.healthline.com/nutrition/15-ways-to-lower-blood-sugar#TOC_TITLE_HDR_1" target="_blank">blood sugar control</a></li><li>aerobic capacity</li></ul></li><li><strong>Improved mood.</strong> High-intensity exercise may also boost your mood. According to a large <a href="https://www.jstage.jst.go.jp/article/jpts/27/4/27_jpts-2014-736/_article" target="_blank">2015 study</a> that analyzed the data of more than 12,000 participants, researchers found a significant link between strenuous exercise and fewer depressive symptoms.</li><li><strong>Lower risk of mortality.</strong> According to a 2015 <a href="https://www.ncbi.nlm.nih.gov/pubmed/25844882" target="_blank">study</a>, researchers found that vigorous activity may be key to avoiding an early death. The study, which followed 204,542 people for more than 6 years, reported a 9 to 13 percent decrease in mortality for those who increased the intensity of their exercise sessions.</li></ul>
How to Measure Exercise Intensity<p>So, how do you know for sure that you're exercising at a strenuous level? Let's look at three ways to measure the intensity of your physical activity.</p><h3>1. Your heart rate</h3><p>Monitoring your heart rate is one of the most reliable methods for measuring exercise intensity. Exercising at 70 to 85 percent of your maximum heart rate qualifies as vigorous exercise intensity.</p><blockquote><strong><strong>WHAT IS YOUR MAXIMUM HEART RATE?</strong></strong>Your maximum heart rate is the fastest your heart can safely beat. To find out what your maximum heart rate is you need to subtract your age from 220. For example, for a 40-year-old person: <ul><li>220 bpm (beats per minute) minus age</li><li>220 – 40 = 180 bpm</li></ul>To work out at a vigorous pace, you'll want to exercise within 70 to 85 percent of your maximum heart rate. For example: <ul><li>180 x 0.70 (70 percent) = 126</li><li>180 x 0.85 (85 percent) = 153</li></ul>For a 40-year-old person, a vigorous training range is 126 to 153 bpm.<br></blockquote><p>You can check your heart rate while you're working out by wearing a heart rate monitor or <a href="https://www.healthline.com/health/how-to-check-heart-rate" target="_blank">taking your pulse</a>.</p>
How to Add Vigorous Activity to Your Workout<p>Adding strenuous activity to your weekly workout routine requires some careful planning. Fortunately, many of the activities that you do at a moderate level can easily be performed at a higher intensity.</p><p>One way of incorporating vigorous aerobic activity into your routine is to do a <a href="https://www.healthline.com/nutrition/benefits-of-hiit" target="_blank">high-intensity interval training (HIIT)</a> workout. This type of workout combines short bursts of intense activity — typically performed at 80 to 95 percent of your maximum heart rate — with recovery periods at 40 to 50 percent maximum heart rate.</p><p>To sustain this level of training, consider following a 2:1 work to rest ratio. For example, a <a href="https://www.healthline.com/health/treadmill-weight-loss#hiit" target="_blank">treadmill workout </a>or outdoor running session could include:</p><ul><li>running at 9 to 10 mph for 30 seconds</li><li>followed by walking at 3 to 4 mph for 60 seconds</li><li>alternating this work-to-rest ratio for 20 to 30 minutes</li></ul><p>Playing a fast-paced sport like soccer, basketball, or racquetball is another effective way to add strenuous activity to your fitness routine. Participating in <a href="https://www.healthline.com/health/benefits-of-a-spin-class" target="_blank">cycling classes</a> or swimming laps are other ways to build more strenuous exercise into your workouts.</p>
Safety Tips<p>Before you turn up the intensity on your workouts, it's important to keep the following safety tips in mind.</p><h3>Check with your doctor</h3><p>If you have a health condition or you haven't been active in a while, make sure you talk to your doctor before you start a high-intensity exercise routine. Your doctor can advise you on a safe level of exercise or how to become more active in the safest way possible.</p><h3>Build up the intensity slowly</h3><p>Going from low- or moderate-intensity workouts to vigorous exercise requires time and patience. While you may be ready to jump in with both feet, the safest way to add more vigorous exercise is to do it in bite-size increments. Pushing yourself too quickly can result in injuries and burnout.</p><p>For example:</p><ul><li><strong>Week 1:</strong> Swap out one moderate-paced cardio session for a HIIT workout.</li><li><strong>Week 2:</strong> Swap one moderate-paced session with a HIIT workout, and also add a circuit strength training session to your weekly routine.</li><li><strong>Week 3 and 4: </strong>Repeat weeks 1 and 2 before you start adding more high-intensity exercise to your weekly routine.</li></ul><p>It's also a good idea to space out your vigorous workouts throughout the week. Try not to do two strenuous sessions back-to-back.</p><h3>Don't forget the recovery time</h3><p>Your body requires more time to recover from a vigorous workout compared to a low- or moderate-intensity session.</p><p>To help your body recover, make sure to always include a cooldown and <a href="https://www.healthline.com/health/exercise-fitness/static-stretching" target="_blank">stretch routine</a> after strenuous physical activity.</p><h3>Stay hydrated</h3><p><a href="https://www.healthline.com/nutrition/7-health-benefits-of-water" target="_blank">Staying hydrated</a> is especially important when you're exercising hard. Not drinking enough fluids can affect the quality of your workout and make you feel tired, lethargic, or dizzy. It may even lead to <a href="https://www.healthline.com/health/dehydration-headache" target="_blank">headaches</a> and <a href="https://www.healthline.com/health/pain-relief/how-to-stop-leg-muscle-cramps" target="_blank">cramps</a>.</p>
The Bottom Line<p>Turning up the intensity of your workout sessions can be an effective way of boosting your overall health and fitness. It's also an easy way to save time when trying to fit a workout into your day.</p><p>To play it safe, always start slow and pay attention to how your body feels.</p><p>While vigorous exercise offers many health benefits, it's not appropriate for everyone. If you have a health condition or you haven't been active in a while, make sure to talk with your doctor before working out at a more strenuous level.</p>
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By Jeffrey Miller
In January 2015, food sales at restaurants overtook those at grocery stores for the first time. Most thought this marked a permanent shift in the American meal.
Solving the Age-Old Problem of Spoiled Cheese<p>People have eaten pasta and cheese together for hundreds of years. Clifford Wright, the doyen of Mediterranean food history, says <a href="http://www.cliffordawright.com/caw/food/entries/display.php/topic_id/16/id/105/" target="_blank">the first written recipe</a> for macaroni and cheese was created in the court of the king of Naples in the 13th century, while <a href="https://food52.com/blog/9916-the-history-of-macaroni-and-cheese" target="_blank">the first reference</a> in an English language cookbook likely appeared in Elizabeth Raffald's 1769 book "The Experienced English Housekeeper."</p><p><span></span>An internet search for macaroni and cheese recipes will turn up over 5 million hits, but many still prefer to get theirs in a box – the kind with pasta that comes in shapes ranging from shells to Pokemon characters, accompanied by a packet of powdered cheese sauce.</p><p>Boxed macaroni and cheese was one outcome of the quest for ways to keep cheese longer. Some cheese gets better as it ages – a well-aged cheddar is one of life's delights – but once most cheeses hit their prime, <a href="https://www.dairyfoods.com/articles/91548-how-to-maximize-cheese-shelf-life" target="_blank">they tend to quickly go bad</a>. Before household refrigeration became common, many retailers wouldn't even stock cheese in the summer because it spoiled so quickly.</p><p>Processed cheese solved this age-old problem.</p>
When Natural Was Nasty<p>Today, food that's simple, pure and natural is <a href="https://theconversation.com/how-was-french-cuisine-toppled-as-the-king-of-fine-dining-66667" target="_blank">all the craze</a>, while <a href="https://apnews.com/c06a1200807c4b82a03452d08d480692" target="_blank">disdain for processed foods</a> is practically a credo among sophisticated consumers.</p><p>But when Kraft's different forms of processed cheese came out, they found widespread acceptance despite their strange textures. The fact that it wasn't natural didn't seem to bother consumers at all. In fact, as international food historian Rachel Laudan <a href="https://online.ucpress.edu/gastronomica/article/1/1/36/93394/A-Plea-for-Culinary-Modernism-Why-We-Should-Love" target="_blank">has noted</a>, back then, "natural was something quite nasty." She describes fresh milk as warm and "unmistakably a bodily secretion." Throughout the history of cookery, most recipes aimed to transform an unappetizing raw product into something delightful and delectable.</p><p>So for most consumers, processed foods were a godsend. They kept well, tended to be easily digestible and, most importantly, they tasted good. Many of them could be easily prepared, freeing women from spending entire days cooking and giving them more time to pursue professions and avocations.</p><p>In some ways, processed foods were also healthier. They could be fortified with vitamins and minerals, and, in an era before everyone had access to mechanical refrigeration, the fact that they kept well meant consumers were less likely to contract diseases from spoiled, rotten foods. Pasteurization of dairy products virtually <a href="https://www.the-scientist.com/foundations/rethinking-raw-milk--1918-65126" target="_blank">eliminated diseases like undulant fever</a>, while foods processed and canned in large factories were less likely to harbor food-borne illnesses that could crop up due to faulty or improperly sanitized equipment used by home canners.</p>
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Some fires won't die.
They survive underground during the winter and then reemerge the following spring, as documented in places like Alaska. They're called "overwintering," "holdover," or "zombie" fires, and they may have now awoken in the Arctic Circle — a fast-warming region that experienced unprecedented fires in 2019. The European Union's Copernicus Atmosphere Monitoring Service is now watching these fires, via satellite.