Even the biggest exercise fans have off days - here’s what could be causing your bad session and how to fix it

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If you’re a keen exercise fan you’ll be au fait with the post-workout euphoria after a successful session pounding the pavements or hitting the gym; and annoyingly, you’ll be equally familiar with the rain cloud of doom that creeps in when you’re in the midst of a bad run or a less than successful weights session or your yoga practice makes you wonder whether you've body-swapped with your granny. Your legs feel like lead and even the peppiest of playlists can get you motivated. On days like this, you often wish you’d never even set your alarm and laced up. Why do some workouts feel doomed from the get-go?

Don't worry, it's not necessarily you, unless of course, you're nursing a hangover. Our experts explain the hidden exercise saboteurs that reveal why your run or workout went badly and how to head them off at the pass.

1. You’re not fully recovered from illness

As we've seen with long-Covid, illness can alter your athletic performance for longer than you think. "If you are recovering from recent surgery or bacterial or viral illness then your athletic performance will most likely be reduced," says GP Dr Johanna Ward . "Even if you feel fine your body might still have some residual fatigue. We know that it takes about six weeks to make a full recovery from major surgery and the same often applies to major bacterial and viral infections such as flu, Covid and pneumonia. Sometimes we see even more prolonged recovery times after illness.

"There is something called post-viral fatigue that refers to a chronic sense of fatigue and energy depletion after a viral or bacterial infection," explains Dr Johanna. "It can take some people months or even years to recover their pre-illness energy levels. This is what we are seeing with long-Covid; prolonged recoveries with people complaining of fatigue and continued breathlessness long after their infection has resolved. This will most certainly affect exercise performance and lung function. I had Covid in early March 2020 and four months later my lung function and exercise performance were still nowhere near what they used to be.”

2. You’re running but not doing other exercise

If running is your passion you still need to make time for other types of exercise. You know that if you do an intense weight session that leaves your muscles aching the next day then your run won’t be as good as it could be, but missing out on weights workout could be equally detrimental and even make you more prone to injury. Running all the time and ignoring strength training or yoga (i.e. building muscle mass and lengthening it) could cause poor performance.

While running improves stamina and body composition it doesn’t improve muscular strength or mobility, explains coach  Luke Worthington  who trained model and actress Sabrina Elba ahead of her wedding to Idris Elba. “If the only exercise you do is run you’ll encounter problems brought on by a lack of muscular strength and this is when we get injured, because our bodies aren’t strong or resilient enough to deal with the repetitive impact running requires.”

Luke recommends combining two weights sessions a week with three runs. He also recommends not getting fixated on doing longer runs each time. “I suggest one distance focused run, one interval focused run and one slower-paced 'technique run'. Here, the effort level is low enough that you can focus on keeping neck, shoulders and fingers relaxed, core engaged and using the glutes as a driving force. When we are working hard our attention tends to be more on just the effort."

He also adds in yoga or Pilates for an active recovery session once a week.

The idea of a technique run is a new one for me; I can get grumpy if I think my run was a wasted session but reframing it as a chance to work on technique is better than sulking if I haven't got as far or as fast as I wanted. Which brings me to…

3. Your head isn't in the game

Some days when your alarm goes off you absolutely do not want to work out and that mindset stays with you as you embark on the exercise. I’ve lain in bed many times mulling over all the elements I don’t want to do – put on trainers, leave the house, tackle the incline – but life coach  Dave Knight  suggests that resetting your mindset is key. The wrong mindset is a major factor in a rubbish exercise session.

“You need to focus on your next step,” he says. “From the moment you think about working out, there are a series of steps before you actually get going, such as getting changed, finding your playlist, getting your trainers on and so on." He recommends thinking about one thing at a time to reduce your 'thinking ahead' – the part where you talk yourself out of the things you don't want to do. "You just need to know about the very next step you need to take. If you do this you can transform the session into something all the more pleasurable.”

4. You’re mouth-breathing

Just being able to breathe at all when you’re exercising can be hard enough. However, breathing right could make all the difference to your session. “Most people breathe in and out through their mouths when they exercise, which is not efficient,” says breathwork expert  James Dowler . “This doesn’t improve oxygen uptake or increase oxygen delivery to the cells. It keeps the body in fight and flight response. Instead, you should breathe in and out through the nose.”

“When you breathe through your nose you carry air deeper into the lungs and over a period of time of nasal breathing when exercising you’ll improve performance, reduce breathlessness and improve recovery “

Warm up your breath before you exercise to make sure you're getting full use of your lungs to power your muscles with oxygen. Pre-workout, James recommends practising diaphragmatic breathing. “Breathe nice and low into the belly and out through your nose. This activates your diaphragm which is not just used for respiration, but for stabilisation of the spine and for posture which helps with functional movement.”

5. You're iron deficient

"If you are  iron  deficient like many women are in their reproductive years, then you are going to have to work much harder to get oxygen to your cells," says Dr Ward. "Exercise will feel much harder under these circumstances. Sometimes iron deficiency comes on slowly such that you hardly notice it but other times it can impact you much more suddenly. For women of reproductive age, I recommend a yearly iron check.

"Fatigue, shortness of breath, brain fog, headaches, pale skin and brittle nails are all associated with iron deficiency," she says. Remember that heavy and intense exercise in itself can cause iron loss so be mindful of changes in your energy levels and get checked by your doctor if you have any symptoms.

"Iron is easy to supplement (ferrous fumarate, ferrous sulphate, Spatone etc) but I would recommend seeing your doctor first before going it alone."

6. There’s too much pollen in the air

If the pollen levels are high, those with histamine intolerance (aka hay fever) might find their workout suffering, explains nutritionist  Daniel O’Shaughnessy . “Fatigue is a symptom of histamine intolerance which can impact your run. Avoiding pollen can be difficult but limiting certain 'histamine foods' which raise your histamine levels, is an option.”

Foods to avoid include:

• fermented foods and dairy products, such as yoghurt and sauerkraut

• dried fruits

• avocados

• eggplant/aubergine

• spinach

• processed or smoked meats

• shellfish

• aged cheese

• alcohol and other fermented drinks

MORE GLOSS: How experts manage their hay fever 

7. You’re eating the wrong pre-workout food

Some people prefer to run on empty, while others need to fuel up first. If you’re in the latter, your pre-workout snack needs to be energy-giving not depleting. “Before you exercise eat something easy to digest such as banana and nut butter, some cheese, smoothie or oats with berries,” says Daniel. “I would advise eating higher  fibre  foods only after your run as they may make you a bit gassy on the way."

Avoid eating refined carbs such as white bread and pastries, as the sugar spike they cause in your bloodstream is quickly followed by a crash. "It will make you feel tired and in need of more food to raise blood sugar levels and energy," warns nutritional therapist  Marilia Chamon . A high protein breakfast just before exercise will also negatively impact your performance as protein is harder to break down and is not used as a source of energy, she says.

If you're having breakfast less than an hour before your run, Marilia recommends fruit, sourdough bread with avocado or nut/seed butter or a smoothie made with one portion of fruit (one portion = 80g = a small banana), half a scoop of protein powder and milk or dairy-free alternative. If you working out within two hours of eating she suggests oats with berries, nuts and seeds or egg and sourdough toast.

As well as breakfast, the dinner you ate the night before can be a deal-breaker, as Marilia explains. "Carbohydrates are the body’s primary source of energy, it is stored in the muscles and liver as glycogen and turned into energy as needed. If you went to bed hungry or did not have enough complex carbohydrates (such as sweet potatoes, rolled oats, whole grains, beans, pulses) the day prior to a run, that will directly impact your performance"

"If you are under-eating and not having as many calories from all macronutrient groups as your body needs in order to perform well, exercise will always be negatively impacted. It takes about five hours for the food you eat to be stored as glycogen therefore having some complex carbohydrates hours before your run will give you that consistent energy supply."

8. It’s the wrong time in your menstrual cycle

We’ve all heard the advice that exercise can help period pain but hormone changes related to your monthly cycle can impact your workout. “In some cases, this is due to heavy bleeding, but more often it is related to fluid retention, which changes in the way muscle store fuel (as the starchy carbohydrate, glycogen), and physical symptoms such as headache or back pain, “explains  Dr Sarah Brewer , medical director at  Healthspan .

“The best time to exercise is when your  oestrogen  and  progesterone  levels are at their lowest. This is between days five to 14 and days 17 to 20 when you can make the best of your glycogen stores in the body and use up stored carbohydrates,” says consultant gynaecologist  Tania Adib . When your oestrogen levels are high they help break down fat rather than use up the stored levels of carbohydrates.

Adds Dr Ward: "Some women report low energy levels during their periods which is largely driven by shifts in oestrogen and progesterone. Some athletes take the combined pill without a break to avoid a period and to prevent blood loss for that cycle. This is entirely safe but is off-licence which means it's not the way the manufacturer has had the drug licensed. There are no known risks to doing this and it may afford you added convenience to skip the bleeding break.

"Hormones are chemical messengers in our body and they signal all kinds of things," Dr Wards says. "Women often feel tired, ‘headachey’ and bloated before their period so training can feel like a hardship at these times. My advice would be to rest if you don’t feel well and to reschedule training sessions if you have symptoms."

9. You've taken a sleeping tablet

We all know that sleep deprivation can cause poor cognitive performance so it's no surprise that physical exercise can feel like wading through treacle if you haven't slept enough. If you have been out for the count for eight hours, but with the aid of a sleeping pill, you still have some lingering effects, says Dr Ward. "Nytol and other sleeping aids can make you feel groggy in the morning a bit like a red wine hangover so don’t be tempted to take them in the middle of the night if you intend to train in the morning.

"They sometimes impair your ability to exercise at intense levels and can increase recovery time. The biggest impact sleep deprivation will have is on endurance sports like long-distance running. Partly this is related to mood and motivation and partly to do with simple biomechanics of the cell."

10. You're menopausal

"Many women describe a catastrophic decline in energy levels as they go through menopausal change which is linked to the steep decline in reproductive hormones," explains Dr Ward. Joint stiffness and aching is a common menopausal complaint so on days when your body aches maybe opt for some restorative exercise such as yoga or pilates rather than a strenuous run.

11. You're dehydrated

The parched post-exercise feeling is a common one but not drinking enough before your sweat session is a key reason you might not perform your best. "Water lubricates the joints and carries oxygen to the cells. The powerhouses inside our cells (called mitochondria) are not able to generate energy without oxygen," explains Marilia. Make sure you hydrate well before you exercise.

12. You’re taking new medication

If you’ve recently started taking new medication and noticed a decline in your performance it could well be down to the pills. “Fatigue is a common side effect of many pharmaceutical drugs including blood pressure tablets, statins, antihistamines, anti-anxiety and depression medication and even antacids can impair exercise tolerance,” says Johanna. Only take medicines if they are necessary and use the smallest therapeutic dose.”

13. You’ve just hit 40

"After the age of 40 our levels of CoEnzyme Q10 decline and our bodies make less of it, " explains Dr Ward. "Coenzyme Q10 is needed by the mitochondria of the cell to help generate energy. Without adequate CoQ10 your legs can feel like led weights on a jog. Q10 can be safely supplemented - you will see it listed as Ubiquinone or CoEnzyme Q10." Try  Super Ubiquinol CoEnzyme Q10 , £50 for 30 gels.

"I tell all my patients over 40 to supplement CoQ10 if they are low because it has powerful antioxidant and longevity effects as well as helping to tap into good energy production. Interestingly Q10 is also thought to reduce inflammation and fatigue after intense exercise so it may help you recover better after your training. So many people focus only on the macronutrients in food like fat, carbs and protein but forget about the micronutrients. These are just as important when it comes to exercise."

If you or a relative are on statins, you may know all about this fatigued feeling, says Dr Ward. "Supplement CoQ10 at 100 to 200mg per day because statins interfere with your Q10 levels."

The main thing is not to get too down on yourself if your workout doesn't go as you'd hoped. "The more we exercise, the more we learn. We start to learn about what makes us tick psychologically, how much we can tolerate physically and what works and doesn't work based on how we feel it went," says Anthony Fletcher, founder of virtual running club Onetrack Club . "Recovery time between sessions is so important but also if you're training for something like a half marathon or full marathon there are going to be days when it's tough, and that's ok, as long as you bounce back from it."

MORE GLOSS: The best ways to recover after intense exercise