If you're a keen gym-goer you might've heard conflicting advice about optimising your workout.

Some people claim that doing both cardio (getting your heart pumping) and strength (getting those muscles pumping) on the same day might cancel out the benefits.

Norman and Tegan unpack what concurrent training is, and what the evidence tells us about its effects.

References

• A Brief Review on Concurrent Training: From Laboratory to the Field - PMC
• Concurrent Training: A Meta-Analysis Examining Interference of Aerobic and Resistance Exercises
• Compatibility of Concurrent Aerobic and Strength Training for Skeletal Muscle Size and Function: An Updated Systematic Review and Meta-Analysis | Sports Medicine
• Concurrent Strength and Endurance Training: A Systematic Review and Meta-Analysis on the Impact of Sex and Training Status | Sports Medicine
• Concurrent training in team sports: A systematic review
• Specific Training Effects of Concurrent Aerobic and Strength Exercises Depend on Recovery Duration
• Concurrent aerobic plus resistance exercise versus aerobic exercise alone to improve health outcomes in paediatric obesity: a systematic review and meta-analysis
• The Effects of 12 Weeks of Concurrent and Combined Training on Inflammatory Markers, Muscular Performance, and Body Composition in Middle-Aged Overweight and Obese Males

Are you constantly getting scolded for pressing your cold feet against your partner in bed? Or told your hands are icy cold?

It’s well known that some people run cold and others run hot. But why does this happen, and does it say anything about your health?

Norman and Tegan unpack the physiology and get into some of the reasons we experience temperature differently.

References:

• Individual differences in normal body temperature: longitudinal big data analysis of patient records | The BMJ
• Gender Matters! Thermal Comfort and Individual Perception of Indoor Environmental Quality: A Literature Review | SpringerLink
• Sex differences and aging: Is there a role of brown adipose tissue? - ScienceDirect
• Cool Temperature Alters Human Fat and Metabolism | National Institutes of Health (NIH) 
• A Review of Cultural Background and Thermal Perceptions in Urban Environments
• Outdoor thermal perception and adaptation of immigrants from cold climates to hot arid climate - ScienceDirect
• Drivers of diversity in human thermal perception – A review for holistic comfort models - PMC

You might've heard a friend complaining about their latest break-out and swearing off dairy products as a result. Or that friend might be you.

It’s a common complaint, but does it have any scientific merit?

Norman and Tegan explore whether consuming dairy can cause acne, and if so, how a glass of milk might lead to pimples.

References:

• The Influence of Genetics and Environmental Factors in the Pathogenesis of Acne: A Twin Study of Acne in Women
• Patient Perceptions About Acne, Nutrition, and a Dietary Information Gap 
• Diet and acne: A systematic review
• Can the right diet get rid of acne? - American Academy of Dermatology Association 
• High school dietary dairy intake and teenage acne
• Effect of Chocolate on Acne Vulgaris - 1969
• Double-blind, Placebo-controlled Study Assessing the Effect of Chocolate Consumption in Subjects with a History of Acne Vulgaris

You might’ve been told by parents, teachers, colleagues, friends of friends to stop cracking your knuckles because it will give you arthritis.

There’s a surprising amount of science going on when you crack a joint, and it suggests there’s very little risk of harming your bones.

But as Norman and Tegan explain, there is one major risk – you could irritate everybody around you.

References:

• Mathematical Model for the Sounds Produced by Knuckle Cracking | Scientific Reports
• Does knuckle cracking lead to arthritis of the fingers?
• The Consequences of Habitual Knuckle Cracking
• Effect of habitual knuckle cracking on hand function
• There might not be anything wrong with your creaky joints - the Health Report
• Misophonia: When sounds really do make you "crazy" - Harvard Health

When weighing up the health risks of getting a tattoo, most people are concerned about the risk infection.

But recently the ingredients in tattoo ink have come under the microscope, with some being identified as potential carcinogens.

Norman and Tegan take a look at the many substances used to create permanent art, and whether they carry any real harm to humans.

References:

• Why Tattoos Stay Put | UCSF Synapse
• What's in my ink: an analysis of commercial tattoo ink on the US market - PMC
• Much ‘tattoo’ about nothing; Tattoo pigment mimicking breast microcalcifications on mammography
• Tattoo ink exposure is associated with lymphoma and skin cancers – a Danish study of twins | BMC Public Health
• Melanoma Arising in Tattoos: A Case Series and Scoping Review of the Literature
• Does tattoo ink give you cancer? - Cancer Council Australia
• 2016 report from the Australian Government’s Department of Health, National Industrial Chemicals Notification and Assessment Scheme

The carnivore diet asks people to eat entirely animal-based, and the most extreme followers restrict themselves to only meat.

Many carnivores claims they feel great — better than they ever have. They have more energy and lose weight.

Norman and Tegan tuck into the reasons why carnivores feel better in the short-term, and the dangers they're inviting in the long-term.

References: 

• Behavioral Characteristics and Self-Reported Health Status among 2029 Adults Consuming a “Carnivore Diet” - Current Developments in Nutrition
• Limitations of Self-reported Health Status and Metabolic Markers among Adults Consuming a “Carnivore Diet” - Current Developments in Nutrition
• Assessing the Nutrient Composition of a Carnivore Diet: A Case Study Model
• Yellowish Nodules on a Man Consuming a Carnivore Diet | Lifestyle Behaviors | JAMA Cardiology

Hot flashes. Night sweats. Aching joints. Sore boobs. Welcome to your body in perimenopause!

In episode one of this four-part series, Yumi Stynes speaks to women in the thick of perimenopause and battling physical symptoms. 

She also sits down with Dr Susan Davis, endocrinologist and world-leading expert on sex hormones and ageing to learn the best treatments for bothersome symptoms and how look after yourself in this stage of life. No sweat!

Essential listening if you're going through perimenopause right now, or for those wanting to know what's over the hormonal horizon.

Do you find yourself complaining that you've got a small bladder, as you run to the toilet for the third time in an hour?

There are many reasons a person might pee more than others, including some scary medical conditions. 

But as Norman and Tegan explain, in most cases your bladder is just deconditioned and you need to get your urinary tract into shape. 

References:

• Bladder control: Lifestyle strategies ease problems
• A randomized double-blind placebo-controlled clinical trial of a product containing pumpkin seed extract and soy germ extract to improve overactive bladder-related voiding dysfunction and quality of life
• Pumpkin Seed Oil Extracted From Cucurbita maxima Improves Urinary Disorder in Human Overactive Bladder
• Prosta Fink Forte capsules in the treatment of benign prostatic hyperplasia. Multicentric surveillance study in 2245 patients

Microplastics are everywhere – they’re in the air, in the water and in our bodies.

There’s plenty of evidence for that, but it’s still unclear what effects these microplastics are having on our health.

Norman and Tegan unpack what we do and don’t know about these tiny specs of plastic, and what you might be able to do about them.

References:

• Ingested microplastics: Do humans eat one credit card per week?
• A review of the endocrine disrupting effects of micro and nano plastic and their associated chemicals in mammals
• Association of mixed exposure to microplastics with sperm dysfunction: a multi-site study in China 
• First evidence of microplastics in human ovarian follicular fluid: An emerging threat to female fertility
• Microplastics and Nanoplastics in Atheromas and Cardiovascular Events | New England Journal of Medicine
• Bioaccumulation of microplastics in decedent human brains | Nature Medicine

• Chewing Gum Releases Hundreds of Microplastics In Your Mouth, Study Finds

This week parts of Australia are preparing to wind back their clocks to mark the ending of daylight saving time.

For a long time the country has been divided about the positives and the negatives of changing the clocks twice a year.

Norman and Tegan look into the health effects of this shift – from the impact on sleep to medical procedures and road accidents.

References:

• Basic concepts and unique features of human circadian rhythms: implications for human health | Nutrition Reviews | Oxford Academic
• Are Daylight Saving Time Changes Bad for the Brain? | Cerebrovascular Disease | JAMA Neurology
• Daylight Saving Time and Acute Myocardial Infarction: A Meta-Analysis
• Daylight savings time transitions and risk of out-of-hospital cardiac arrest: An interrupted time series analysis
• Embryo transfers performed during daylight savings time led to reduced live birth rates in older patients | Journal of Assisted Reproduction and Genetics
• Daylight saving time as a potential public health intervention
• Does lowering evening rectal temperature to morning levels offset the diurnal variation in muscle force production?