Currently most countries around the world have enacted self-isolation and quarantine rules to help flatten the curb and reduce the spread of COVID-19. An unfortunate by-product of these restrictions has been the closure of gyms and fitness studios, coupled together with a large number of people now working from home. This has made exercising more challenging and reduced people’s motivation to exercise resulting in more sedentary behaviour and reduced physical activity.

At present the physical activity guidelines recommend at least 150mins per week of moderate to vigorous activity. This means exercising at least to a level where you are unable to complete a full sentence without taking a breath. Why is physical activity important? There is a growing body of evidence that shows how beneficial exercise is for a raft of conditions, it helps to reduce your risk of developing chronic preventable diseases like diabetes, obesity and cardiovascular disease, as well as reducing your risks of certain types of cancers including breast, colon, liver, kidney. Additionally, it is beneficial for improving balance, bone health, quality of life, cognition, sleep, mood, mental health and immunity among others. 

To combat this decline in physical activity and to motivate people to keep exercising throughout the COVID-19 pandemic, the Shannon Clinic together with the help from some great friends who are professional athletes, we have started the #getmoving initiative. On the Shannon Clinic Instagram page we are dropping a series of videos every few days this week from pro athletes who are here to encourage you to keep exercising and to show you how easy it is to exercise without access to a gym or equipment.

We hope that you enjoy the videos as they are released, and they motivate you to keep exercising, we also ask you to share the videos and if you have any requests or questions please comment below the posts. Ultimately, we would like spread the word as far and wide as possible and would like more pro athletes to post similar videos of encouragement. I thank my wonderful friends including WTA players Demi Schuurs and Nicole Melichar, Brazilian Jiu Jitsu champion Ben Hall, ATP players Bruno Soares and Alex Peya for helping out, so get out there and get moving!

With the current COVID-19 pandemic creating global disruption, uncertainty and with many countries enforcing society lockdowns, it is making physical activity and exercise more onerous. However, one of the few exceptions to the lockdown rules is exercise, so lets examine the evidence on exercise and immune function.

It is well known that regular bouts of exercise lasting up to 45 minutes of moderate to vigorous exercise is beneficial for immune defence, particularly in older adults and those with chronic diseases. This type of exercise is beneficial for the normal functioning of the immune system and is likely to help lower the risk of respiratory infections/illnesses. However, there is debate within the scientific community whether acute bouts of vigorous intensity exercise leads to a period of immune suppression post exercise.

There has been a long held concept in exercise immunology developed in the 1980s and 1990s called the “open window” hypothesis which proposes a J curve relationship between exercise intensity and infection risk. Which is supported by the belief that athletes who engage in high volume endurance training experience a greater incidence of Upper Respiratory Tract Infections (URTI) compared to those who are less active. Until recently this concept has remained relatively unchallenged.

The “open window” hypothesis suggests that following a prolonged (>1.5hr) and vigorous acute bout of exercise or following chronic intense training (>1.5hr on most days) there is an “open window” which results in an increased risk of opportunistic infections such as URTI’s. The three principles underpinning this concept are:

1). Infection risk increases after prolonged vigorous aerobic exercise

2). Acute bouts of vigorous exercise can lead to temporary reductions in salivary immunoglobulins resulting in higher risk of opportunistic infections

3). A period of post exercise reduction in peripheral blood immune cells resulting in a period of immune suppression.

J Curve – relationship between the risk of infection and level of exercise intensity

Recently though there has been emerging evidence suggesting this concept may be outdated. There is evidence, albeit small that indicates international athletes suffer from less URTI than national athletes. This raises the likelihood that infection susceptibility is more likely multifactorial including genetics, sleep, stress, nutrition, travel, circadian misalignment and increased exposure risks due to close proximity of crowds rather than being directly attributed to acute or chronic bouts of vigorous training. This also indicates that international athletes are potentially better supported, have access to better education helping them to improve their life-style behaviours over national athletes resulting in lower risks of infection.

Secondary to this, evidence supports the opposite of the three principles upholding the “open window” concept. With no changes seen in mucosal immunity which has previously been flagged as an indication of immune suppression. The reduction in blood immune cells (primarily lymphocytes) 1 to 2 hours post exercise reflects a transient and time dependent redistribution of immune cells to peripheral tissues resulting in a heighten state of immune surveillance and regulation leading to enhanced antibacterial and antiviral immunity, not suppression of the immune system.

Further research is needed to confirm or refute the “open window” concept however, it currently appears that the infection risk post vigorous exercise is more likely to be associated with a multitude of other factors rather than purely post exercise immune suppression. So for athletes and non-athletes the message remain the same during COVID-19, regular moderate to vigorous exercise is beneficial to enhance immune function to reduce the risk of bacterial and viral infections including URTI’s. And remember that good hygiene practices (washing hands regularly, not touching your face), physical distancing, getting good quality sleep, reducing stress levels and eating healthy wholefoods are the keys keeping your immune system in peak condition.

Find out more information on COVID-19 here.

The Benefits of HIT/HIIT Training

Exercise and physical activity are extremely important for our overall health and wellbeing. With evidence showing physical activity improves; quality of life, sleep, cognition, physical function, insulin sensitivity, while reducing the risks of; clinical depression, dementia, a raft of cancers and chronic preventable diseases, as well as anxiety, blood pressure, weight gain and falls. The current recommendations for physical activity are for 150 minutess per week of moderate to vigorous exercise, this means exercising to an intensity where it is still possible to maintain a conversation but with difficulty. High intensity (with/without intervals) training is a great way of efficiently reaching that 150 minutes per week mark with a host of added benefits.

High Intensity Training (HIT) / High Intensity Interval Training (HIIT)

HIIT refers to exercise that occurs in frequent short burst or “sprints” of high intensity exercise, with recovery periods. The sprints can last from 30 seconds to 4 minutes, with recovery periods lasting anywhere from 1 to 4 minutes and repeated sprints of 2 to 6 cycles per session. For true HIIT to be achieved, heart rate (HR) needs to reach 85-90%+ of max HR during the sprint effort. This is the key difference with moderate continuous training (MCT) where HR will only reach 60-70% of max HR.


In healthy individuals HIT/HIIT programs have been clearly shown enhanced exercise capacity, muscle strength and muscle oxidation compared to MCT. It may also improve cardiovascular fitness and function, as well as anxiety and depression severity. It has been associated with improvements in these same variable in individuals with cardiovascular disease, spinal arthritis and multiple sclerosis, in addition to reducing the disability associated with these diseases. In obese and overweight individuals it is as effective in the short-term as MCT at modest reductions in body fat and waist circumference, which suggests it may be a more time efficient way to exercise. Additionally there is also evidence showing it is well tolerated and has greater improvements in disability and exercise capacity in individuals with nonspecific low back pain when compared to MCT.

What Type of HIT/HIIT Program?

One of the appealing features of HIIT programs are how time efficient they are, especially when compared to MCT. In addition to this, HIIT programs appear to result in similar or greater endurance performances and VO2max (a measure of fitness) when compared to MCT.

Cardiovascular protocols utilizing short intervals (30 seconds or less), for 5 minutes or less, performed 4 or fewer times per week will assist in developing VO2max in the general population. However, the greatest improvements come from longer sprint intervals (2 minutes or longer), higher volume (15 minutes or longer) over a longer duration (4-12 weeks). Resistance training HIT protocols are typically defined as more than 70-80% of a 1 repetition maximum, performed at a maximum of 1 set of 12 repetitions.

Finally, for anyone considering a HIIT program it is important to note that even though HIIT appears to be safe for most individuals, consulting a health/medical practitioner to determine if a HIIT program is safe for you is extremely important before you start any HIIT program.

The Injury Risks From Running

Running season is in full swing at the moment with a plethora of fun runs available, covering 10km, 21 km (half marathon) and 42.2 km (marathon). However, the motivation to run doesn’t necessarily involve competing with others, it could be for stress relief and mental health, general fitness, personal enjoyment or part of a weight loss regime. Regardless of the motivation, injury risks are associated with running where 19% to 79% of runners will experience a running related injury in a given year. Even with improvements in shoe technology helping runners run faster, the injury rates have remained reasonably unchanged since the 1970’s when the modern running shoe was first introduced.

Risk Factors For A Running Injury

Known risk factors related to injury risks in male and female runners include a previous history of an injury, especially in the case of muscle strains and fractures, running with insoles/inserts, and a rapid increase in distance run. There is mixed evidence that absolute high distances (consistently running high distances each week) may or may not be involved with injury risk. Overall, females have a lower injury risk than males however, additional risk factors for women include older age, a longer weekly running distance (48-64km), running on concrete and wearing running shoes for 4-6 months. Whereas males are more at risk if they are restarting running after time away, have been running for less than 2 years and run more than 64km per week. It is also well established that 80% of all running injuries are overuse, this coupled together with the known risk factors for running injuries indicates that training loads play a potential role into why runners experience high injury rates.

Running Load + Injury Risks

What does all of this mean for someone who likes running, it says that although running injuries have multiple causes managing training loads is extremely important to mitigating the risk of injury. With some evidence showing that absolute high training loads can have a protective effect on injury in certain sports, the key is to minimize acute load increases or training spikes. In simple terms this means training loads need to be consistent with small increases in load. A load based model has been put forth called the acute:chronic ratio and it essentially says that the current weeks training load should be between .8-1.3 times the load of the previous 4 weeks of training, if the load is 1.5 times or greater the risk of injury increases.

How To Reduce Your Risk of A Running Related Injury

In lay terms this means if someone is running 5km 2 times per week for 4 weeks and then decides to add a third longer run of 10km a week in the 5th week, they greatly increase their risk of an injury. Does this mean pulling out the calculator to crunch the numbers to get your ratio right, not really. There are plenty of fantastic running training plans available for all levels of runners and all distances, programs that factor in gradual load increases, rest periods and tapering. Running should be enjoyable and injury free regardless of the motivation, so to reduce the risks of sustaining an overuse injury manage the load, gradually increase the kilometres run, avoid training spikes and allow for rest periods. If you do sustain an injury be sure to promptly consult an appropriately trained sports based practitioner/physician.

High intensity interval training (HIIT) is hugely popular in the exercise world at the moment, leading to an explosion of “HIIT” style group classes and work outs. Unfortunately though, many of these classes and work outs are not actually HIIT programs as used in the research literature. Therefore the results individuals achieve won’t be inline with the results HIIT research supports. Is this a bad thing? Probably not, if it means people are exercising this far outweighs the difference in health outcomes comparing HIIT and vigorously intensive classes.

An example of a true HIIT program which was used in a research study using HIIT to treat patients with heart failure involved 4, 30 second sprints at 90% of max HR on an inclined treadmill with 4 minute rest intervals, building up to 6 sprints.